Emotiva MPS-1 shutting down? Amp gurus help

Posted by: SirQuack

Emotiva MPS-1 shutting down? Amp gurus help - 03/22/07 09:15 PM

Hello everyone,

Before I call Lonnie at Emotiva tomorrow, I thought I'd get some feedback from other big dog owners.

I've had my mps-1 chassis with 2 epm300 mono's for a few months now and have been very happy. I am driving new Axiom m80v2's (stable 4 ohm) which should not be a problem for the mps-1. I am also using my Denon 2805 as a prepro to the mps-1.

Tonight while my wife was gone I had things cranked up pretty loud, reading about 100-106dB's on the SPL meter from 13ft away. I was listening to a little Doobie Brothers Greatest hits and slowly pushed the Denon volume knob to 0, then + 5, then +10.....then.....+13dB (which was max for the Denon with the left/right calibrated at +5dB to achieve 75dB SPL). Anyway, the MPS-1 went into shutdown mode and I could hear the fans running.

I then turned it back on and was playing the Beatles LOVE CD at around +5dB on the Denon master volume, first the left amp shut down, shortly followed by the right amp on the mps-1. Basically, the blue lights turn off.

So what is going on? I've heard the Axiom m80's will shut down some AVR's, but the mps-1 is stable to 2ohms according to the manual. Is it my Denon? I figured that being a prepro, it is just passing the signal to the mps-1 to amp, so there should be no strain on the Denon?

I read the review by Gene at Audioholics, talking about pushing this mps-1 to unbelievable limits with no problems. Any input would be appreciated.

Randy
Posted by: Wid

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/22/07 09:35 PM

Randy, it seems you were just pushing the amps beyond what they can handle. I don't think it gets any more complicated than that.
Posted by: CosmicVoyager

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/22/07 09:41 PM

I agree. I never have had any issues with my M80's shutting down any of my amps. Do you have good ventilation?
Posted by: JohnK

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/22/07 09:49 PM

Randy, this is very basic, but there may be a possible loose strand somewhere in your wiring that vibrated into a short at very high sound levels. Re-do your wiring just in case. There appeared to never be a problem with the 2805 alone, and no, it has nothing to do with this when it serves as a pre-pro.
Posted by: Spoiler

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/22/07 10:11 PM

A guess on my part, but Sirquack didn't run the 2805 with the M80's alone, just the M60's, correct?

Wow.. and I thought I was cranking my system to insane levels! My M80's are calibrated to +7db to achieve 75db SPL on the 3805, and being driven by the Outlaw monos. I had them set to large and cranked the volume knob to +7... it scared me to hear an extra "popping" from the M80 woofers... they were being overdriven!! Needless to say, I'm back to the 60hz crossover. The Outlaws, though toasty to the touch, never tripped. (This was after about 45 min. pounding them) On the other hand, I haven't cranked the Denon to full volume, though +7 is close. Keep us updated!


Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/22/07 11:11 PM

Thanks guys. Based on Gene's review at audioholics, he ran the MPS-1 at 120+ dB's for hours at a party he had for his columbian friends, and the MPS-1 didn't make a sweat. I really can't believe I'm overdriving it Rick?

The amp is in the lowest shelf of my AV rack with plenty of breathing room on top and back. The basement stays pretty cool year around.

I will recheck the wiring, but find that hard to believe as I'm very picky on my connections, but one should never assume.

Normally, I don't play music this loud, somewhere in the 90's is more than fine. With the efficiency of the 80's, it does not take much.

Also, keep in mind my room is 8100 Cubic Feet, so I have a lot of air to fill. From the primary movie seat I was fluctuating from 98-105 or so dB's during different passages of the music when having it really cranked up.
Posted by: Wid

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/23/07 08:56 AM

What was the size room that Gene had the amps in? As you noted you do have a very large room to fill. I would be a bit disappointed in the amps if that's all they can muster. My Rotel can put out 105 to 110 db for quite some time and not go into over load. Then again it's not being done in a 8100 cubic ft room.
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/23/07 10:51 AM

I believe Gene was having a party outside.
Posted by: MarkSJohnson

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/23/07 11:03 AM

Quote:

outside



THAT qualifies as a big room, I think!
Posted by: Hutzal

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/23/07 11:28 AM

Randy,

To eliminate all the problems that may be associated with it. Why not try to take the amp out of the rack and in some open space (if your RCA cables are long enough). See if that makes a difference in the shut down. If it does, then you know it has to do with air circulation.
Posted by: MarkSJohnson

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/23/07 11:42 AM

Quote:

Why not try to take the amp out of the rack and in some open space (if your RCA cables are long enough).



Or just put a box fan near it while playing at the same volume as the other night.
Posted by: Hutzal

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/23/07 11:51 AM

Quote:

Quote:

Why not try to take the amp out of the rack and in some open space (if your RCA cables are long enough).



Or just put a box fan near it while playing at the same volume as the other night.




Thats probably the more easy way of doing it
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/23/07 12:27 PM

I talked to Lonnie and he said he did not think it was a cooling issue. I have plenty of breathing room above, behind, and below, so that should not be an issue. He did say I could move one mono over to the next slot to create a little more breathing room within the chassis if I want.

After talking to Lonnie, I'm pretty confident that I was just pushing the amp to its protective mode. Since it came right back on he was sure there was no problem with the amp, it was just the circuitry portecting the amp. He said he could tell me how to turn that off, but he would not recommend it.

If you keep in mind that my measurements were being taken from the seated position, about 13 ft away, and I was getting peaks up to around 106-108dB's. If I move closer to the source by half the distance, 6.5ft away, that gives you and increase of 6dB or 112-114dB, then again cutting this by half to get closer to the one meter (3ft) range, your talking 3 ft with 118-120dB's. In reality, I'm sure I was hitting higher peaks, just not watching the SPL meter closely.

Based on my 95dB 4ohm Axioms, 120dB's would be pushing the 300Watt limit of the amp, so I guess it makes sense that it would shut down.
Posted by: Wid

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/23/07 03:22 PM

Quote:

Randy, it seems you were just pushing the amps beyond what they can handle. I don't think it gets any more complicated than that.




As someone had mentioned
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/23/07 05:11 PM

You just stated it like they are a piece of junk. I'm sure driving a 4 ohm speaker in the equation makes a difference as well.

I will do some more testing, but if I'm getting 120dBish at 1 meter, that is pretty dang loud.


Posted by: CosmicVoyager

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/23/07 05:43 PM

Quote:


I will do some more testing, but if I'm getting 120dBish at 1 meter, that is pretty dang loud.





Yes, it is. And if you you want to continue to hear detailed music. You might want to consider reducing your db intake a little .

BTW, I checked out your site! Very nice! It's been a year or so since I've been here.
Posted by: Wid

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/23/07 06:27 PM

Quote:

You just stated it like they are a piece of junk. I'm sure driving a 4 ohm speaker in the equation makes a difference as well.






I don't know how you read that into what I said.
Posted by: snakeyes

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/23/07 08:30 PM

Quote:

Quote:

You just stated it like they are a piece of junk. I'm sure driving a 4 ohm speaker in the equation makes a difference as well.







I don't know how you read that into what I said.



It is easy to see that:
Randy, it seems you were just pushing the amps beyond what they can handle. I don't think it gets any more complicated than that.
EQUALS
Randy you your amps you bought are some real POSs. when you run with the M80 clan you go Rotel or you go home BIATCH!!!


JK JK JK JK
Posted by: richeydog

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/23/07 08:53 PM

^^^

lol...
Posted by: JohnK

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/23/07 09:26 PM

Randy, a quick point about sound levels at various distances: the 6dB per doubling of distance figure takes into account only the direct sound and would be applicable to listening in an anechoic chamber. It doesn't tell the story in real-world listening situations in reflective rooms where the level of the reflected sound has to be added to the direct sound to get the total combined level and at some point(typically maybe 5-6' feet away from the speaker)becomes greater than the direct sound. This was discussed some time ago here when Gena made some level measurements. The result is that far less power is required beyond the standard one meter rating distance than the 6dB figure would imply.
Posted by: Mojo

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/24/07 12:34 AM

Randy,

Compare the input voltage specification for the pre-amp input on the Emotiva to the output of the Denon. Are you perhaps saturating the Emotiva's input when you turn up the Denon's gain? This is a long shot but you never know.
Posted by: Haoleb

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/24/07 02:17 AM

Quote:

Thanks guys. Based on Gene's review at audioholics, he ran the MPS-1 at 120+ dB's for hours at a party he had for his columbian friends, and the MPS-1 didn't make a sweat. I really can't believe I'm overdriving it Rick?

The amp is in the lowest shelf of my AV rack with plenty of breathing room on top and back. The basement stays pretty cool year around.

I will recheck the wiring, but find that hard to believe as I'm very picky on my connections, but one should never assume.

Normally, I don't play music this loud, somewhere in the 90's is more than fine. With the efficiency of the 80's, it does not take much.

Also, keep in mind my room is 8100 Cubic Feet, so I have a lot of air to fill. From the primary movie seat I was fluctuating from 98-105 or so dB's during different passages of the music when having it really cranked up.





I just read this review since i thought 120db + seemed a bit excessive. Ive had my system going at 105db and that was LOUD, Louder than I would ever listen. I cant imagine anyone playing music at 120+db, And unless he was using some sort of club speakers even hitting those levels would be hard.

He actually said that the amp shutdown a few times during the course of the night at those levels.

Quote:

I estimated they were hitting SPL levels in excess of 120dB - at least until the MPS-1 went into protection mode and shut down. This happened a few times during the course of the evening and I was curious as to why, since I heard no signs of distress from the amp, even at these insane levels.



Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/24/07 12:32 PM

I'm going to recheck my wiring today to make sure I don't have a strand or something touching, which I highly doubt. Last night I had a bunch of friends over and we watched to movie "The Marine". At some time during the movie the left amp shut down because after it was over I noticed the blue light turned red for that channel.

I was sitting clear over to the right side of the room in front of the right m80, so I didn't notice the left channel missing until I looked over at the amp.
Posted by: bugbitten

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/24/07 12:52 PM

Randy,

Are you still in the 30 day return window?

This just doesn't sound good.
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/24/07 01:06 PM

Not sure, I can check.

I'm beginning to wonder if it is not the preout voltage of my Denon, which I think is 1.2v and possibly it is clipping at the fuller power to the MPS-1. Below is a portion of the audioholics review I found, which appears to worry about some AVR preouts may have potential problems:

"I measured the voltage gain of the MPS-1 via balanced and unbalanced inputs and found the following:

Unbalanced: Av = 27dB
Balanced: AV = 26dB
Typical THX Product
Unbalanced Av = 29dB
Balanced: Av = 23dB (6dB lower than balanced)
It's a standard practice in most consumer and pro audio equipment that the gain structure of unbalanced to balanced is about 6dB less for the latter for power amps. The preamp therefore usually has a +6dB boost via the balanced outputs to compensate. I was a bit puzzled that the MPS-1 didn't follow this convention. However I didn't find it to be much of an issue, especially since the balanced outputs were about 3dB hotter than convention. It took about 1.65Vrms to drive the MPS-1 to full power. Had the MPS-1 followed standard convention of Av = 23dB some preamp sections of receivers such as the Yamaha RX-V2500 may not have been able to drive it to full power since that receivers' preamp outputs clip when output signals exceed 2Vrms. My personal criteria for amplifier gain structure is that it should be able to hit full power when driven with 2-3Vrms. The MPS-1 fell well within this criteria."


There is another guy on AVSforum that is having a similar problem with his Denon 2807 and his 4ohm Ref 1's.

I am not a electronics expert, but could this voltage thing be playing a part, or could it be my 4ohm 80's causing the problem?
Posted by: Mojo

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/24/07 06:32 PM

According to the manual, the Denon's pre-amp out is 1.2V. And according to the Audioholics review you posted, the MPS-1 should be good to at least 2V. So I now doubt that's the problem. Your speaker impedance does not affect the Denon at all since it's buffered by the MPS-1. You may want to check your speaker to see if it is damaged. If your Ohm meter reads less than 2 Ohms, that's probably your problem. If you don't have a meter, connect the speakers directly to the Denon.
Posted by: JohnK

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/24/07 09:19 PM

Randy, first a comment on what Gene said about the gain. When a balanced connection with two wires carrying signals into the amp(instead of the one with a regular coaxial cable)is used, the two voltages combine for a 6dB increase(a voltage double is 6dB, compared to the 3dB increase for a power double). That's why, as Gene pointed out, that the gain for the balanced input is typically designed to be 6dB lower, to keep things even regardless of whether a balanced or unbalanced input is used. The Emotiva's higher gain is an interesting curiosity, but as Gene commented, it isn't of any particular significance. The gain on the unbalanced input(which you're using)is a typical number which the 2805 can surely provide enough voltage to satisfy, and even if it couldn't, the result would be distortion in the preamp, not the amp shutting down.

Yes, re-do the connections even if they look good, because those little wires can be very sneaky, and they seem to cause trouble a lot more often than the amp actually being driven too hard does. As I commented, the 6dB with doubling of distance number isn't adequate for a complete picture of power use and the dB numbers you give shouldn't cause a problem with the M80s which are "an easy 4 ohm load". I recall you mentioning when you got the M80s how your 2805 made them "sing", and it wouldn't be surprising if it still does if you connect it to the M80s to check for a shutoff(unless an internal short has developed in one of the M80s).

Despite the assurances that you've received, there may be something wrong with the Emotiva.
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/24/07 09:44 PM

Thanks Mojo and John

I'm pretty sure there is nothing wrong with my new m80's they sound great. I'm now thinking there most likely is nothing wrong with the mps-1 either. I re-checked all the speaker connections and everything was fine.

Today, I hooked my Denon back up to my m80's. I picked 4-5 different CD's, everything from Classical, Josh Groban, Jazz, and some good ole rock and roll.

I re-checked my calibration of all speakers using the Denon's test tones and noticed I was running them about 1dB to high, no big deal really, anyway they are now at +4dB for an SPL of 75dB on the meter.

From 13ft away, with the Denon main volume on 0dB, that gave me an average of 100dB (peaks upto 105dB or so) on the SPL meter. As I tested various songs, and gradually raised the volume, I noticed the sound from the Denon, although still good, did appear to be straining a little at the higher levels and seemed to be less detailed and harsher to my ears. With the SPL meter now set to 110dB range and the volume turned up to around +5to6 I was seeing peaks going beyond 110dB on the meter. If I do my math correctly, this was really working the Denon, and I could tell by the sound, I was most likely approaching its limits and headroom was gone.

With the mps-1 hooked back up, things seemed much different. The same songs never showed any strain at any levels. I never cranked the volume all the way to the max like the other day, but even at +6-10 on the Denon the mps-1 had no problems, was not even warm to the touch, and the fans never came on once.

I'll keep an eye on things, and most likely will never have a need to turn the Denon volume to its max, that is just to loud.
Posted by: Mojo

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/25/07 11:06 AM

I'm glad to hear your speakers are healthy. You are suggesting that perhaps the Denon is being taxed when you turn up the gain. I can understand your Denon getting taxed when connected to the speakers but it should not be getting taxed when it's connected to the MPS-1. The MPS-1 should have a very high input impedance (>100KOhms with very small capacitance in the order of hundreds of pF or less). But even if the Denon is being burdened, this still doesn't explain why the MPS-1 is shutting down. I don't mean to scare you but I strongly suggest you don't over-look this. You may have discovered a marginal design and/or marginal components that could get worse with use. And it could come back to haunt you after the warranty has expired. Along these lines, find out how Emotiva burns this product in and whether or not the burn-in covers this sub-system.
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/25/07 04:43 PM

Thanks mojo for your concern. Emotiva is like Axiom, in that they care about their customers and will do whatever it takes to fix any issues. I don't think your familiar with their company.

Here is a bit of history, they are a Engineering and Design company that has been around for many years designing the guts/electronics used in many of the high end ($$$$$$) amp companies on the market. I won't disclose any of those names per my promise to them, however, they are under confidential agreements with those companies, and in return they were able to make their own product, using the same insides they designed for others.

Anyway, I know many people using their products on AV123 and AVSforum that are highly regarded in the AV community, and they give high praise.

In fact, I had a small issue with my amps voltage regulators when I first purchased the mono's, and they shipped me two modified amps within 2 days that were personally lab tested by the owner to make sure my problem would be resolved, and it was.

I do appreciate your concern and advice though...Randy
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/25/07 04:50 PM

As I mentioned earlier in this thread, there is another person I've been talking to on AV123, and he is having the same issue with his Denon 2807, MPS-1, and 4ohm Ref 1's.

I think the amp was just engaging its protective circuitry as I approached its limits. Based on my figures, 119 dB would require 256 watts. The MPS-1 is rated at 300 watts into 4 ohms. I was taking my measurements from 13 feet away, as I moved closer to my m80's, I was easily reaching 120dB and beyond during peaks.

ps: I did have my hearing buds in to protect my ears.

Below is some more information I found on Audioholics review by Gene. I will be following up with Emotiva.

" Later on the bench I discovered that the MPS-1 was engaging its soft clipping circuit at around 37-38Vrms into 8 ohm loads and while driving 4 ohm loads the MPS-1 delivered about 31Vrms into 4 ohm load unclipped (note the RBH T-2 System has 4 ohms impedance). However, as I increased the signal level just below clipping, I was able to achieve 33Vrms at 1kHz but the amp shut off when frequency was brought down below 60Hz. It was apparent the sensitivity of the soft clipping circuit / limiter needed some tweaking. I informed Emotiva of my findings and they quickly resolved this issue, sent me a new sample and I didn't observe this problem thereafter"

And This: "I was able to achieve a maximum unclipped power of 175wpc into 8 ohms with Vin=1.65V Vout=37.39V unbalanced and about 255wpc into a 4 ohm load with Vin = 1.42V and Vout = 32V. Once I exceeded these measurements, the clamping circuit kicked in rounding off the signal and dramatically increasing distortion. Based on this, I would rate this amp to be a 175wpc into 8 ohms and 270wpc into 4 ohm, not 200wpc / 300wpc 8/4 ohm respectively like Emotiva rated in their literature."

Posted by: bridgman

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/25/07 08:35 PM

>>ps: I did have my hearing buds in to protect my ears.

Wouldn't you get better sound if you just turned the volume down and took out the earbuds ? If you have to wear earplugs, you're just playing too darned loud
Posted by: MarkSJohnson

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/25/07 08:56 PM

Plus, your amp wouldn't keep shutting down!

(Running and looking for cover!)
Posted by: bridgman

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/25/07 09:23 PM

Good point. I don't know why Randy didn't figure this out on his own, he seems like a pretty smart guy
Posted by: JohnK

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/25/07 10:13 PM

Randy, the only thing that I'd think would be even mildly disturbing in the additional quotes from Gene's test is the protective circuit shutting it down as he described, but this supposedly was corrected and you'd think that this also applied to later production units.

As far as the numbers in the second paragraph, they all figure and are good. 1.42v in and 32v out is a gain of 27dB[20 log(32/1.42)], as Gene mentioned elsewhere, and the resulting power from Ohm's Law(P=Vsquared/R)is 1024/4= 256 watts.

By the way, my calculations for 106dB at your listening position came up about 100-110 watts into 4 ohms.
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/26/07 02:40 PM

Thanks John, I"ve been on the phone with Emotiva today. They assured me my problem was not the Soft Clipping issue that Audioholics talked about. Also, every new unit after that point was fixed based on the Audioholics review.

We are looking at a few things, and they are willing to send me out some new modules if I say the word. This is unlikely, but they said it is possible that the Bias adjustment may be a little off on my units, and causing the amp to shut down prematurely. They are still leaning towards that I may be bouncing of the upper limit of the amplifier.

I just don't think that is the issue, but maybe. They also recommended that I DO NOT use my Tripplite surge/conditioner, and just plug the amp right into the wall outlet directly. They also said they recommend, if possible, that a person uses a dedicated line just for the amp. The Tripplite can be limiting what the amp is receiving, especially during dynamic times when the amp needs more current. Also, the amp, being a class H design, has built in protection, so they do not recommend a surge/conditioner.

In regards to Audioholics findings of 256 watts into 4 ohms, they assured me that they are in fact 300watts into 4 ohms as stated. They are not sure of the exact test that was used to get these figures (mainly what equipment/ load banks, etc.), but they assured me and will back their specs up every day of the week that their amps do produce the power that they are rated. This is something Emotiva takes very seriously and they do not play games with the figures.

In regards to me worrying about the Denon's 1.2v preout rating, here is their response:

The EPM-300 amplifier modules are set to 27db of gain with a 0db reference input level of 1.5 volts nominal. That is to say that the amps have 27db of gain and that it would take a steady state tone at 1.5 volts to get maximum output. Now the amps can easily take a voltage input well in excess of this with no problems to recreate the dynamics of the source material. However, if you pre/pro is rated at 1.2 volts, then yes it is possible to get a clipped signal out of the pre/pro, but unlikely. The 1.2 volt rating is a nominal rating that means under a steady state test that is what it will produce before clipping. However, music is not a steady state; it is all about the dynamics, so the actual output could be well in excess of 2.0 volts.
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/26/07 02:51 PM

Ok, after plugging the amp directly into the outlet, as I mention above, I was hoping the problem was resolved.

From the seated position, 13ft away, my m80's are at +5dB to achieve 75dB on the SPL meter, using the Denon's test tones.

Should I be using the test tones on the receiver, I would think 75dB is 75dB, no matter what the source of the calibration setup?

Anyway, I turned on some music with the Denon main volume on -5dB (pretty loud) and things sounded great. So I eased it up to 0dB on the volume, still sounded great. The meter set to "fast" with C-weighting was basically averaging 100dBs. Even when I walked up to about 3 ft of either m80, was not even hitting 110dB's, at least what I could see visually with the SPL meter.

So, I went back to my easy chair from 13ft away and eased the knob up to +5dB. After about 10 seconds, the left channel amp turned off, followed by the right channel shortly after.

I guess the Tripplite had nothing to do with anything. I will be calling Emotiva back to see what they think. I wish I had another Receiver to rule out my Denon preouts. There is another guy on Av123 having the same problem with his Denon 2807 running Ref 1's (4ohm).

Is it just the combination of my 80's and Denon. Emotiva is going out of their way to help me, and they assure me this Class H amp, their top of the line, is designed to be pushed hard. This is so frustrating.

I'm wondering if I should be calibrating my speakers, NOT using the Denon?

Randy
Posted by: Hutzal

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/26/07 02:58 PM

Randy,

I agree with your consensus, a calibration to 75db is a calibration to 75db. Your SPL meter doesn't lie. Regardless of calibration, you are still not pushing the amp as much as other say it can be pushed.

I don't know much about denon's at all, can't help you there.

Perhaps you have a fellow audiophile friend locally that could do a listening test with his reciever or something.
Posted by: real80sman

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/26/07 07:55 PM

Wasn't Dennis having similar problems with his Outlaw amps shutting down, even though they were supposed to handle the 80s?

Didn't he switch to..... oh, the brand escapes me. Craig had one for awhile also...

Regardless, with the other brand, he could pound at triple digits all day.
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/26/07 07:57 PM

Ok, I did some testing just now, thanks to Wid for giving me the idea. I hooked up my rear Qs8's to my amp. They are rated at 400 watts also, so what the heck. Now I know they are 6 ohm, versus the 4ohm 80's. But this might help to tell us what is going on if anything.

Also, just for safety, I turned my crossover to 100hz, since the Q's were now hooked to the left/right channels and would be really tested.

I used the song "Take it on the Run" by REO. With the Qs8's, I gradually turned up the volume from 0, to +3, to +6, to +10. Even though they are rated at 400watts, I was a little worried, so I didn't go beyond +10, however, I did leave it at +10 for a couple of minutes. Everything was fine and neither monoblock turned off.

So then I rehooked up my 80's and started the same song over. At 0, everything was fine and the sound was killer. then I turned it to +3 for a minute still ok, then +4 BAMMMMMMM as soon as the kick drum and bass guitar kicked in during a dramatic part of the song when they say "Take it on the run baby", the left main shut down. If I would have let it go, eventually the right amp would have shut down also, but I just turned everything off and was pissed.

So, I will call Emotiva tomorrow and tell them my findings.

Thanks for listening, no pun intended...
Posted by: Ken.C

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/26/07 08:17 PM

Yeah, Dennis switched to Parasound Halos. Which are significantly more expensive than Emotivas. Significantly...

OTOH, he was also driving 5 M80s and 2 QS8s to 115 dB, so it's a little bit different.
Posted by: richeydog

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/26/07 10:18 PM

Dennis was able to shut down the Parasounds in that big ole room of his. He was approaching nearly the same spl's as Randy, but with a Rocket setup(1000's x 2, 850's x 3, qs8's x 2).

We just figured that he played them to their capacity, and then joked that he should get rid of the A21's in favor of some JC1's...

I still would like to know what is going on with Randy's M80's and MPS-1...
Posted by: bridgman

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/26/07 10:26 PM

From what I remember, the Outlaw amp simply couldn't get rid of heat fast enough when running at sustained high volumes with mostly 4 ohm speakers. In his case there was an "overtemp" light that came on (and everything was really hot ) so it was pretty clear what the problem was.

Does the Emotiva have enough idiot lights to indicate whether this is a temperature or current limit shutdown ? I would re-read the thread but I'm running at about 6 bps on dial-up right now (if I meant 6 Kbps I would have *said* 6 Kbps ) so I can't bear to go read the thread again, sorry.
Posted by: Mojo

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/26/07 11:18 PM

Quote:

In regards to Audioholics findings of 256 watts into 4 ohms, they assured me that they are in fact 300watts into 4 ohms as stated. They are not sure of the exact test that was used to get these figures (mainly what equipment/ load banks, etc.), but they assured me and will back their specs up every day of the week that their amps do produce the power that they are rated. This is something Emotiva takes very seriously and they do not play games with the figures.





Randy, every manufacturer has the best intentions. You may want to ask Emotiva to show you the test specification (complete with test set-up) and signed test results to verify the above claim. If they take it that seriously, they should have documented proof so that they and their customers can rest easy.
Posted by: HomeDad

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/26/07 11:22 PM

I've run my Aragon 2005 at some pretty extreme levels powering 5 speakers and never had a problem, I didn't check my SPL levels but my wife did call from across the street and tell me to turn it down.
I'm betting there is a problem somewhere other than just driving the amp to hard.
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/26/07 11:27 PM

Each amp has the following:

Blue Led - Power module is installed, online, and ready.

Amber Led - Power module is installed and powered on but is in a standby situation waiting for audio signal or external trigger.

Red Led - This indicates a fault condition. A fault condition is one or more of the following:
.excessive operating temprature
.excessive current (short circuit)
.DC on the outputs

When my amps shutdown I get a red led for that channel that shuts down.
Posted by: richeydog

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/27/07 12:20 AM

What is the temperature of the amp when it shuts down? Cool, warm, or hot?
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/27/07 09:37 AM

It is still pretty cool, I had not been running it very long.
Posted by: bridgman

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/27/07 12:05 PM

OK, that's good news.
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/27/07 04:02 PM

They told me they will make this right for me, and I totally believe they will. If not they said, they will take the unit back. They are sending me some new amps, and Lonnie is personally runnning a QA on them before they leave. He wants to explore his thought on the Bias adjustment on the amps I have as possibly being set slighly off.

The amps have two Bias adjustments, a manual one that is set during production, and an automatic one that alters itself based on the situation.

He also said that the owner of the company is running 4 ohm speakers as well that are far more expensive than Axioms, and has no problems. He does not think it is the m80s. Only time will tell.
Posted by: CosmicVoyager

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/27/07 04:28 PM

Quote:



He also said that the owner of the company is running 4 ohm speakers as well that are far more expensive than Axioms, and has no problems. He does not think it is the m80s. Only time will tell.




I don't think expense is a good way to measure quality, but that's just my opinion. The guy didn't need to bring that up.

I'm glad that there taking care of you!
Posted by: KlipschGuy

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/27/07 04:53 PM

Hi Randy, sorry to hear about your luck, hope it gets fixed soon. I have the MPS1 and have a 20x15x8 Ht that is totally dead, i.e., soundblocked, cloth walls etc. I was driving the Klipsch Rf83 with my Yamaha Rxv2500 as pre/pro to 100db with no probs..volume would be at up to -2 depending on source recording. Then added the EMO DMC1 and now the Eagles Farewell tour DVD for example plays at 95db at a setting of -32!!!!..lol..so something is different on the Yammy, I was at -6.
I will let you know how the MPS1 handles the M80's when I get them on Thursday although I may not be cranking them to 115 db at my listening position which is 12' from the speakers. I like it loud but, holy moly? I may try it out though and see what happens.
Hope you get it figured out

Regards, Chris
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/27/07 05:28 PM

tleigh,

Lonnie was only responding to my question if the problem is driving 4ohm speakers. He just mentioned that the owner had no issues, as well as thousands of other people. Axiom makes great speakers, but there are many brands out there in a higher league and do cost much more. And, there are some that can't hold a candle to Axiom, that cost much more.
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/27/07 05:30 PM

chris, that is interesting about the difference from -6 to -32 just by adding the DMC-1. I'm anxious to hear your findings.
Posted by: Wid

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/27/07 07:28 PM

You must admit it is a little odd that an employee of a budget amp company would bring up the cost of speakers in any context. I find that just a bit odd.
Posted by: dllewel

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/27/07 09:39 PM

I concur.
Posted by: grunt

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/27/07 09:50 PM

Quote:

You must admit it is a little odd that an employee of a budget amp company would bring up the cost of speakers in any context. I find that just a bit odd.




Axiom envy?
Posted by: JohnK

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/27/07 10:16 PM

Yeah Randy, amplifiers vary in their gain and preamps vary in their output at a given setting, so the number on the volume control for a given loudness can be all over the place. Having a lower number is just the result of design decisions and isn't of any particular significance.
Posted by: KlipschGuy

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/28/07 08:03 AM

Randy, just a thought. What gauge speaker wire are you using and how long are the runs?
Chris
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/28/07 09:55 AM

Thanks for the thought, however, this should not be the issue. I have good quality 12 AWG wire all the way around. The run lengths are insignificant for my situation.
Posted by: MarkSJohnson

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/28/07 01:17 PM

Crossing over at 80Hz? In case the amps are sweating deep bass.....(?)
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/28/07 09:29 PM

Mark, should I not be using a crossover of 80hz anymore and sending the LFE to the sub? Keep in mind that my Denon only has one crossover setting, so lowering it would affect all speakers in my setup.
Posted by: MarkSJohnson

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/28/07 09:56 PM

Hey Randy:
No, just the opposite. I thought by some chance your amps were working extra hard because for some reason, your pre-pro had all the speakers set to "large".

I know it was a real basic question, but it seems like you're trying everything else to figure it out so I thought I'd throw it out there just in case....
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/28/07 10:28 PM

aaahhhh I see, sorry for the confusion. I still have my Denon set to 80hz crossover and all speakers to small. However, I could set my 80's to large and I think the amp would have no issues.

By the way, Emotiva sent me two new amps yesterday, should get them tomorrow. Also, received one today for my center channel.
Posted by: bridgman

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/28/07 11:19 PM

>>However, I could set my 80's to large and I think the amp would have no issues.

Is this what you meant to post ? Wouldn't the amp have to push more signal out (the bass below 80 Hz) to achieve the same SPL ?

I still think taking out those earplugs is your best bet. I'm sure Mark agrees with me on this.
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/28/07 11:25 PM

Yes John, that is what I was saying. I most likely will not do this, however, it is my understanding that these amps would have no problems with that load. I believe many people that use seperates run 80's to large, but I could be wrong.

Anyway, I should have my new amps in the next day or so, and then I will know if the problem I've been having is resolved.

ps: thanks for responding using your 20bps connection.
Posted by: Wid

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/29/07 06:48 AM


Even if you ran the M80s at large the Emotiva should be able to handle it. I think you just ran into some bad luck with your amps. Lets hope the new ones will do the trick.
Posted by: Spoiler

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/29/07 07:44 AM

It seems unlikely from reading this thread that both amp modules would have the same issue.

But here's hopin' I'm wrong!....
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/29/07 12:37 PM

It is possible that the same amps came of the mfg line at the same time and placed in inventory, then shipped out to me, but not sure.

Hooked up the 3rd mono to my center last night and watched Taladega Nights. I now most of you won't believe this, but it did seem that the center performed better and the dialogue was easier to understand. It seemed to have better detail.
Posted by: N24color

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/29/07 02:40 PM

I'm a beliver in what you heard..I had been using an Onkyo 801 as my AVR. Recently I purchased a 5-channel amp and now I'm using my Onkyo as a pre/pre and oh my gosh imho it made a wondeful difference in all 5 channels. For me its like a veil was removed from my speakers. I have my M80's set to large - I hear better seperation of sound with that setting on my system compared to small setting.

M80
VP 150
QS 8's
Onkyo pre/pro
Halo A51 5-channel
Posted by: KlipschGuy

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/29/07 02:41 PM

Hey all, Just got my M80s and all I can say for a very quick first impression is WOW! They sound fantastic, I can't believe the bass these things pound out, incredible. I was really surprised though how much those drivers move, LOL, they were just flying back and forth to Keb Mo, hehe.

Randy, I have the same problem with the MPS1, at about 105db from 12' away the Left channel shuts down at -20db on the DMC and the right at -15. I spoke to Dan Laufman who is the President of Emo and he has set his top engineer onto the problem, it will be corrected and we have nothing to worry about. He said that the MPS1 should make your ears bleed before shutting down, so there is a problem and we will be taken care of.

I have complete faith in these guys, hang in there!

Chris
Posted by: Lorenzo1000

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/29/07 02:53 PM

After all these replies I think i't's time to pull out my Ratshack meter and do some checking. I'm running the 80's with my pioneer 84 receiver and 2 ATI 1502's each in mono mode. I'll have to see what level of DB's I can get them to produce. It's starting to sound more like Tharkun's problem he had with the outlaw 7 channel amp where it just wouldn't play nice with his 80s.
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/29/07 10:21 PM

Thanks Klipsch Guy, , man you really need to change your name. I have spoken to Dan only via posts on AV123. I'm fairly certain Lonnie has spoken to Dan about the problem I am having. There is another guy on AV123 with Ref 1's, which are bookshelf but still 4 ohm design speakers. He is having the same issue with his Denon 2807. At first we thought it was the Denons.

Anyway, Lonnie was supposed to send me some replacement amps asap. I have not received them yet. I will follow up to see if he has spoken to Dan.

thanks for the info..
Posted by: Lorenzo1000

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/29/07 10:55 PM

All right not that it proves anything but I got my Pioneer receiver running in pure direct with my ATI 1502 amps each in mono feeding my 80's. I turned the volume up to 0 on the scale and they were hitting peaks of around 108 decibels on the meter from about 14 feet away. Good grief that is LOUD!!! Who on god's green earth would ever play their speakers that loud for any length of time?

So Randy when you are having trouble are you only using your 80s or are you also using your other speakers and sub?
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/29/07 11:00 PM

During my testing, I was just playing music using Direct mode using my m80's and ep600 sub.
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/29/07 11:27 PM

Just an update from the President of Emotiva.


Don't worry guy's. We're looking into this and will advise in detail ASAP.

It is definitely not a lack of output capability; I have no concerns about this. My feeling is that the protect threshold had drifted on this production run for some reason.. . it's a subtle thing, as the modules test OK, but under the right dynamic conditions they are apparently inhibiting too easily. We'll get to the bottom of this right away.

Regards,
Dan
__________________
Dan Laufman
President
Emotiva Audio Coporation

Posted by: Lorenzo1000

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/29/07 11:32 PM

Have you seen the Dodge Nitro commercial where he gives a guy a boost and the nitro driver guy gives it some gas and the car literally explodes 50 feet straight up in the air? I can see it now, "Hey Randy turn it up a little" then BOOM and there goes the roof to Randy's house...

Nitro
Posted by: bridgman

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/30/07 12:39 AM

>>My feeling is that the protect threshold had drifted on this production run for some reason..

This sounds right, since the amps weren't getting really hot.
Posted by: JohnK

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/30/07 01:55 AM

Yes, as Mr. Laufman suggested, this may be a case of the protective circuits for temperature and/or current being set too low. I recall that about four years ago there was quite a bit of internet discussion about Pioneer Elite receivers(generally quite capable with 4ohm loads)shutting down all over the place. It didn't appear to be fully explained, but the situation apparently was corrected by servicing the protective circuits on the units.
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/31/07 08:32 PM

I'm trying to use this SPL Calculator to get a better idea of how many watts I'm really using to achieve the SPL dB's I'm seeing when the Emotiva amps go into protective mode.

This calculator takes into account speaker placement in relationship to the walls, as well as if your using 1 or more speakers during the measurements.

The question I have is that it appears to be for an 8ohm speaker? So, how do I interpret the results when considering my m80's?

Based on what I'm figuring so far, there is no way I'm maxing out this amp?
Posted by: JohnK

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/31/07 08:53 PM

Randy, that calculator isn't adequate since it doesn't take into account the contribution of room reflections to the total sound level at the listening position. Beyond a certain "critical distance", which may be about 5-6' in typical home listening rooms, the reflected sound is greater in level than the direct sound and remains relatively constant at longer listening distances. As I mentioned before, I made a rough calculation using certain assumptions(of course you may have heard about the physicist who was helping a farmer with a problem, and began "First, assume a spherical cow")and estimated that at peaks you were using about 100-110 watts.
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 03/31/07 11:11 PM

So even though I've accounted for this by having all my first reflection points covered (walls/ceiling), and have full corner bass traps, this does not help make it more accurate?
Posted by: JohnK

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/01/07 12:31 AM

That was one of the "assumptions", i.e. the reverberation time of your room.
Posted by: Mojo

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/01/07 01:05 AM

Quote:

The question I have is that it appears to be for an 8ohm speaker? So, how do I interpret the results when considering my m80's?




The model is agnostic of speaker impedance. 1W of power into a speaker is 1W of power regardless of its impedance.
Getting back to your question about how much power you were pushing, I'd say you were around 100 to 120W. I'm saying this based on readings I've taken of my environment and I'm factoring in that your room is better treated than mine.
Posted by: KlipschGuy

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/01/07 01:20 AM

Randy, as Dan has said, you are no where near maxing out your amp, standby for a fix soon, those EMO guys are excellent at what they do, it is a glitch. New modules for us soon..
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/01/07 10:54 AM

The two modules I received Friday, with the Bias adjusted from Lonnie, are doing the same thing. Now, these were sent out prior to Dan Laufman's statements about looking into this issue. I will contact them on Monday to let them know the replacement amps are doing the same thing.

I wish I could find more people with 4 ohm speakers and the MPS-1, and ear plugs, willing to test my theory. So far the people I've talked to on AV123 and AVSforum all are using 4 ohm speakers.

Based on my own math calculations (A:) and using the above SPL Calculator(B:), here are my guesses:

A: With my SPL meter placed at 1 meter in front of either speaker and the Main Volume knob on the Denon at +3 I'm getting readings of an average of 110dB's on the meter. This is using C-Weighting and "fast" so I can really see the peaks when they happen.

This would be using about 32 watts to achieve 110dB's. During dynamic parts of the music, the needle would "occasionally" jump up to 115-116dB's, but only briefly. I'm thinking this would be using around 128 watts to achieve. So I'm not even close to a steady 300 watts reading..

B) From the 12ft seated position, figuring in 2 speakers, and figuring in 2-4ft from walls, I figure I'm using about 10Watts to achieve the 100dB's average reading. With peaks of around 106dBs, it would be around 45watts.

From 3ft away I would only be using 8 watts to achieve 110dB's and 32 watts to see the higher peeks.

Again, nowhere near the 300 watts it would require to shut this thing down.
Posted by: Mojo

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/01/07 11:51 AM

Randy,

I agree with your calculations and the conclusion. Here's another long shot for you to take up with Emotiva.

I understand that they use a modular card cage. So the card cage has connectors that mate with the modules. If these connectors aren't made of the "right" material, their contacts can oxidize over time particularly if they have been sitting on a shelf unmated. So if Emotiva builds the cage and inventories it until need it many months later, the contacts may have oxidized. When they oxidize, their electrical resistance increases. The amplifier's output voltage is proportional to the resistance of the load being driven. If the resistance of the load increases too much, the output voltage can be driven to the supply rails and the amp shuts down. The load that the amp is seing consists of the speaker impedance and the parasitic resistance of the contacts.

The same effect can happen if the connectors are not mating with enough contact force. This is a long shot as every manufacturer should be aware of this kind of an effect but I have seen it happen a few times before with home entertainment and industrial gear.
Posted by: KlipschGuy

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/01/07 12:02 PM

My modules all looked pristine when I installed them about a month ago, of course i didn't look Inside the cage. Good thoughts MoJo but I really think its a setting thats gone adrift in production as Dan told me, but who knows? In the meantime I can still play my system friggin LOUD and hard so its not an issue as long as they fix it shortly. If it was not working i would be on the phone for new modules asap.
I have to go to work till late Mon night so hopefully they will have some news by Tues or Wed.

Have a good weekend all,
Chris
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/01/07 12:15 PM

The amps use a photo eye type setup, so they really don't make any contact with the cage other than the AC recepticle to power each amps own power supply. I don't think we are deally with an oxidizing issue. These amps don't sit in inventory very long before they get shipped out.


Posted by: KlipschGuy

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/01/07 12:38 PM

Here are some pics om my MPS1 being setup.







Posted by: Mojo

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/01/07 01:18 PM

That is one sweet design! I love that toroidal transformer on every module. And now that I see how it's built, I see that there are no connectors that can oxidize. I am green with envy. Like Randy said, this is most likely a manufacturing issue and you guys have nothing to worry about.
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/01/07 02:11 PM

And here are some of my pics.














Posted by: michael_d

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/01/07 05:22 PM

Why you guys are getting all worked up over decibel levels is baffling to me. That is irrelevant to what’s happening. The amps or part of the assembly is defective. Send them back or get your money back. If the amp is rated for a continuous 4 ohm load, and it shuts down driving a 4 ohm load, something is wrong with the speaker (short to ground), something is wrong with the amp, or the manufacture fudged their numbers. They should not be going into over current protection driving M80’s. Drivers are not some sort of mystical electron vacuum that sucks more current out of an amp that it is designed and rated to supply. They only draw available max current supply of the connected amplifier’s transformer, which your amps are not supplying without shutting down.

The simply fact that your Denon did not shut down should tell you something.
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/01/07 05:51 PM

Not sure why you think we are getting worked up, we are simply using our findings to prove that we are not reaching the limits of the amps. Isn't that what AV people do?

If you read above, the company has already stated they realize there is an issue, that is why they have been working with me by next day shipping other amps to resolve my issue. I've talked to them on numerous occasions and am very impressed with their service.
Posted by: pmbuko

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/02/07 08:14 AM

Maybe God's just trying to tell you to save your money?
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/02/07 10:06 AM

God and my wife have an agreement to get me interested in something different than AV.
Posted by: michael_d

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/02/07 10:21 AM

Quote:

Not sure why you think we are getting worked up, we are simply using our findings to prove that we are not reaching the limits of the amps. Isn't that what AV people do?

If you read above, the company has already stated they realize there is an issue, that is why they have been working with me by next day shipping other amps to resolve my issue. I've talked to them on numerous occasions and am very impressed with their service.




Oh I dunno…maybe it was the fifty or so posts in this thread going back and forth over decibel levels gave me that impression.
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/02/07 06:18 PM

Update: Well I worked with Emotiva today over the phone. For starters, they went out and purchased a Radio Shack Analog meter like mine. In their labs they use much higher quality test equipment, for example, "Audio Toolbox" meters. This way they could try to recreate what I was seeing on my meter.

Anyway, their initial findings was that the amp was truely meeting the specs of 300 watts into 4 ohms, in fact, it was actually reading 380 watts when the amp protection kicked in.

Another finding, was that the Radio Shack meter is great for calibration of speakers, but not really the best for lab test readings. During the dynamic parts of songs where the RS meter would jump from 110dB to 115 or 116dB, their more accurate Audio Toolbox meters were showing 20+dB jumps.

Now, the conversation moved onto the amps Wave Form Limiter? I really didn't understand what this does, but it sounds like this was the main reason the amps are shutting down. Emotiva mentioned the amps will do 780 watts RMS no problem, from past tests in the lab, however, I believe this Wave Form Limiter protection restricts what gets passed onto the speakers?

I talked to Axiom, and was told the 80's have been run for 2weeks straight at 24hrs a day at 700 watts continuous with peaks reaching 1100 watts, while testing the new amp line. So I know the Axioms can handle the wattage.

Resolution:

Emotiva showed me with very detailed instructions/pictures how to remove one of the resisters which gives the Wave Form Limiter its input signal. I"m not worried about making this modification, as I've worked a little on circuit boards/soldering, etc.. Basically it just involves removing this resister with some small snips, no problem.

The tests Emotiva did today, showed that with the amps being pushed very hard, they will produce just over 1KW. The Resistor being removed is where the Wave Form limiter gets it’s input signal from. Now by removing it, this will disable the limiter whereby making the amplifier like most amps on the market today. The amp is still a dual tracking class H design and the protection circuit is still in place, only the limiter has been disabled.

Without the limiter it is possible to get out peaks in excess of 1KW if pushed hard enough which would easily toast most speakers. I would not recommend this modification if your not having a problem, and would contact Emotiva if you are...

Randy
Posted by: Ken.C

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/02/07 06:22 PM

So ya gonna do it? It sounds like if all you're doing is testing the limits, well, you've found them! If you're going to listen to it at those levels, well, I'm going with the other guys who say you should probably take out the earplugs and turn it down.
Posted by: Mojo

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/02/07 07:21 PM

Randy,

I have to admit that I don't understand how the waveform limiter caused the amp to shut down. But if that's what Emo says, then that's how it must be.

I suggest you ask Emo how distortion is affected when you remove the waveform limiter. The waveform limiter is very much like the dynamic range compression function on your Denon. When the rate of change of amplitude of the signal gets above a certain threshold, the limiter engages and reduces the amplifier's gain to prevent clipping of the waveform. So if you remove the limiter, you now run the risk of clipping the waveform. Clipping is bad as it introduces harmonics. These harmonics not only sound terrible but they can also fry tweeters.
Posted by: bugbitten

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/02/07 08:39 PM

Quote:

Update: Well I worked with Emotiva today over the phone. For starters, they went out and purchased a Radio Shack Analog meter like mine. In their labs they use much higher quality test equipment, for example, "Audio Toolbox" meters. This way they could try to recreate what I was seeing on my meter.

Anyway, their initial findings was that the amp was truely meeting the specs of 300 watts into 4 ohms, in fact, it was actually reading 380 watts when the amp protection kicked in.

Another finding, was that the Radio Shack meter is great for calibration of speakers, but not really the best for lab test readings. During the dynamic parts of songs where the RS meter would jump from 110dB to 115 or 116dB, their more accurate Audio Toolbox meters were showing 20+dB jumps.

Now, the conversation moved onto the amps Wave Form Limiter? I really didn't understand what this does, but it sounds like this was the main reason the amps are shutting down. Emotiva mentioned the amps will do 780 watts RMS no problem, from past tests in the lab, however, I believe this Wave Form Limiter protection restricts what gets passed onto the speakers?

I talked to Axiom, and was told the 80's have been run for 2weeks straight at 24hrs a day at 700 watts continuous with peaks reaching 1100 watts, while testing the new amp line. So I know the Axioms can handle the wattage.

Resolution:

Emotiva showed me with very detailed instructions/pictures how to remove one of the resisters which gives the Wave Form Limiter its input signal. I"m not worried about making this modification, as I've worked a little on circuit boards/soldering, etc.. Basically it just involves removing this resister with some small snips, no problem.

The tests Emotiva did today, showed that with the amps being pushed very hard, they will produce just over 1KW. The Resistor being removed is where the Wave Form limiter gets it’s input signal from. Now by removing it, this will disable the limiter whereby making the amplifier like most amps on the market today. The amp is still a dual tracking class H design and the protection circuit is still in place, only the limiter has been disabled.

Without the limiter it is possible to get out peaks in excess of 1KW if pushed hard enough which would easily toast most speakers. I would not recommend this modification if your not having a problem, and would contact Emotiva if you are...

Randy




I just happened to be in the Emotiva lab Friday while Robert and Dan were doing the second of these procedures for another unamed client. I watched as they tested an amp module using a subwoofer. I can attest that the amp was pushing beyond 300 watts.

I will have more to say later about my visit with Emotiva.

I also went back today and bought an MMC-1.
Posted by: pmbuko

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/02/07 10:33 PM

Here's an analogy:

Randy: Doctor, when I try to maintain my 100-yard dash pace throughout the marathon, I end up puking after the first 1.5 miles. What's wrong?

Doctor: Nothing's wrong. Stop doing that.



I do see how wanting an amp to perform to its specs is desirable, even if you'll never have to use the rated capacity without earplugs, isn't really all that strange. I'm sure Emotiva is grateful for your out-of-the-lab, real world tests and feedback.
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/03/07 10:27 AM

Ok, here is my latest information from Emotiva, without going into great detail on their amp design.

"I really can’t go to deep into the design or operation of the wave form limiter as this is technology that is proprietary. What I can do is give you a basic overview of what it does. This type of limiter is what would normally be found in broadcast equipment like what is used at radio stations, television stations etc. It is used and employed to prevent the outgoing signal from clipping and the same principle of operation applies here. The limiter looks at the incoming signal in relation to the output as well as a number of other variables like current draw, rail voltage, etc. To understand what it does, you need to understand what the design criteria of the amp is. The EPM-300 amplifiers are designed to produce 300 watts RMS into a 4 ohm load unclipped. If the amplifier is pushed beyond this point a normal amplifier will go into clipping which could easily cause damage to the speakers. You see when an amplifier clips the distorted wave form starts to square off which generates harmonics across the bandwidth relative to the fundamental frequency. It is these harmonics that contribute to an increase in power output from the amp that will super heat the voice coils and cause them to expand and deform where by they will either rub against the motor structure and fail or will simply burn through the wire in the voice coil again casing the speakers to fail and to make it all worse this is not always apparent as the distortion is often masked by the level of the fundamental frequencies. Now with the limiter, if the amp is pushed beyond the designed levels, the limiter will engage where by reshaping the wave form and bringing it within a safe operating range and thereby protecting the speakers. So by removing R12, you will deactivate the limiter and the amp will now go into clipping which could cause possible damage to your speakers. So are you getting more power without the limiter? Not really, you see the amp will still only produce 300 watts RMS clean into a 4 ohm load, but now it can be pushed well beyond that but the signal will now be clipped."

So I really have a decision to make here guys and I need your help. I know the 80's can handle gobs of power according to my above statements, but what good is that if the amp driving them is clipping?

I really love this amp as the sound/power is great, however, once in a while when I audition, people like to hear something cranked up a bit. If I can't go past +3 on my Denon knob once in awhile without the dang thing shutting down, what good is it...

I could with the Denon, however, I could easily notice the Denon was straining and clipping, it must not have the same limiter inside.

This drives me nutzzzzzz.
Posted by: pmbuko

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/03/07 10:47 AM

Quote:

however, once in a while when I audition, people like to hear something cranked up a bit.




Did you buy the Emotiva for you or for people??

If it only shuts down when you play it louder than you'd ever listen to, I fail to see any real problem. The M80s can handle gobs of clean power, but clipped power can damage any speaker.

The choice is simple: If you can get over the fact that you can't successfully demo TEH AWESUM P0WER that the Emotiva is capable of (in the lab, at least), then keep it. If it'll eat at you constantly, return it.
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/03/07 10:59 AM

I don't think you guys are following everything. You have to keep in mind my room is 8,000+ cubic feet, a lot of volume to fill.

100-106dB's from 12ft away is loud, but I don't think it is apples to apples say for someone in a 12 x 15 room or so.

Randy
Posted by: Hutzal

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/03/07 11:02 AM

Randy,

Like pmbuko says, how often are you really going to be listening to those levels?

On the other hand, if you are the type of person that it will just bug you when you're watching movies at reference level (75db) and knowing that you can't go over 100db...and it is constantly on your mind, then I would return the Emotiva, get a different amp that can give you the levels you are wanting.

Perhaps call Axiom about their 8 channel amp and see when it will be released

I am one of those types of people that wants everything to be perfect, something like this would indeed bother me greatly and I would probably return the amp.

Just my 2 cents!

-Hutz
Posted by: Lorenzo1000

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/03/07 11:13 AM

I say return it and look for a good used amp on Audiogon. If you are only using it for the 80s it shouldn't be too hard to find a reasonably priced 2 channel amp that will do the job.
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/03/07 11:28 AM

thanks Lorenzo,

My goal in all of this was to eventually to drive my entire system with this modular/chassis amp design. Being a monoblock design, you can add modules as budget allows. I already have 3 amps driving my l/c/r with plans to purchase their 2-channel modules for the surrounds. Having everything in one chassis and saving space was plus also.
Posted by: Lorenzo1000

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/03/07 11:36 AM

There are 3 channel Acurus amps at 200 WPC that run around $500 - $600 on Audiogon all the time. Other good amps for the $$$, ATI, Sherbourn, Sunfire Cinema Grand, Marantz Ma 700 monoblocks, Marantz mm9000.
Posted by: Ken.C

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/03/07 11:57 AM

Isn't 100dB at the listening position 100dB, no matter how big the room is? I'm confused.
Posted by: michael_d

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/03/07 12:10 PM

Send them back. Or, that is what I’d do – if you care. I’ll say it one more time. It is irrelevant how much power your amps are outputting or if it’s loud enough for you or your friends or your neighbors. They are not supplying maximum available current without shutting down. This should not be happening. They claim to be rated for a 4 ohm load, so they should be able to carry the load without shutting down. It just doesn’t get any simpler than that. You praise Emotiva for working with you. Well, they should be. Their product is not performing as it should. They just don’t have that many customers with a set of speakers to push their amps to their limit, or are willing to give it a try if they do own them. You have the speakers and you are giving their amps a heck of a work out. How many other M80 owners actually push them this hard??? Not that many, if any. It’s just too loud and probably scares the hell out of most sane individuals that are not experiencing sever hearing loss.

For comparison’s sake (only because I know you like comparisons), when I had my M80’s in my great room powered with my Rotel RB 1080, I could pin the volume to max for as long as I wanted and it would not go into over current or clipping. (Granted, it wasn’t all that long as it was simply too friggin loud for me and my neighbors.) When I moved the 80’s to the theater room and bought some Wharfedale Opus 2’s for this system, I can still pin the volume for as long as I like without shutting the amp down or clipping. The Opus 2’s are a 6 ohm speaker not nearly as efficient as the 80’s, but with much larger drivers. In other words, they have comparable current requirements even though the resistance is higher.

My great room is 28 X 32 with a vaulted, 23’ ceiling peak and 10’ walls. Much more cubic space than your room.

My Axioms are now being powered by a lil ol’ Marantz receiver with a measly 125 wpc / 8 ohm. Twin M22’s as a center (4 ohm) and the M80’s across the front. Q8’s all around the back. Same thing as when the Rotel was driving them……volume pinned and no shut down and no clipping. And this is just single amp with six taps for the channels.

My past three HK’s (745, 7300, 7200) exhibited the same qualities……no clipping or shut down with the volume pinned.

Your Emotiva is defective. I don’t care what sales pitch they throw at you or how you or anyone else tries to rationalize it, it should not be shutting down. If you’re “over driving” them now with the volume at around 90%, what will the threshold be in a year?? 80%, 70%??

Emotiva’s look like one heck of a bargain and they sound like a great company to work with. But they are young and their product will have some growing pains until they get the bugs worked out. I’m sure that if you are patient, and they are open to the possibility that they have a problem here, you may be OK in the end, if you decide to keep it. If they continue to come up with excuses trying to convince you that the problem is your speakers and not their amps, I’d not hesitate to ask for my money back.

Why don't you send Alan an email and get his opinion? He's gone through this numerous times already trying to smoke amps / receivers to see if they will drive Axiom products.
Posted by: pmbuko

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/03/07 12:22 PM

It is, but it takes less power to reach that level in a smaller room, due to room reinforcement. All else being equal, (and barring peculiar geometries which result in significant cancellation) the sound waves that sum at the listening position will have greater amplitude in a smaller room due to reflections traveling a shorter distance.
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/03/07 12:24 PM

I appreciate everyone's advice.

Just to make sure we are clear. They have never said it was my speakers. Dan and Mark from AV123 have been in this business for over 30 years and I'm pretty confident that he is being honest.

The amp IS giving me 300 watts RMS into 4ohms. Their top engineers, while Bugbitten was at their facility can prove this time and time again with any of the amps they test.

They are NOT defective, whatever you think. It has all been explained above. Any amp WILL clip if driven past its limits, I don't care if you have a Rotel or whatever. You say yours did not clip, what facts or equipment do you have to back that statement.

My little Denon will also go past the same volume point, but start to sound like crap and you can tell it is straining/clipping. The Emotiva sounds like many more expensive amps I've heard upto the point that you've reached its limits, then the built in protection kicks in, not sure why that is a defect.

Bugbitten, I'm anxious the hear about your recent visit.
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/03/07 12:25 PM

thanks Peter, on that positive note.
Posted by: Mojo

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/03/07 12:55 PM

Randy,

I don't understand why the waveform limiter is causing the amplifier to shut down. The explanation of a "bad" waveform limiter is even more suspect when you were sourcing less than 120W from the amplifier. I am sorry but it just does not make sense to me.

Here are some critical questions that you may want to ask yourself as you work towards making a decision:

1. Am I happy with an amplifier that is rated 300W into 4 Ohms and is only capable of less than 120W into 4 Ohms?
2. If I am happy with 1, am I still getting good value for my money?
3. Do I trust Emo?

I feel for you as you try to resolve this issue but at least it's not a death sentence .
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/03/07 01:42 PM

Did you not read the response further up on this page? My findings of 120 watts, were by using a Radio Shack SPL meter. Yes I trust Emotiva. If you follow AV123 over the years you would be more familiar with the founders of the company. As mentioned above, their testing over the last week with true lab equipment is showing 20+ dB jumps during dynamic passages. So, from one meter distance when I'm showing peaks of 116dB's, they are seeing 130dB's, which if you do the math exceeds the 300watts spec.

I don't claim to be an engineer like some of you, and don't claim to understand all the math. I do know they are a strong company, that makes great products for themselves as well as many top brand name companies.

I just wish some of you would do a little reasearch on a company before jumping to conclusions, like there giving me some sales pitch. I know you didn't make that statement.

And no, I don't work for Emotiva, yet.
Posted by: Mojo

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/03/07 01:55 PM

Randy,

Yes, I did read your previous post.

When they claim 300W into 4 Ohms, I interpret that as RMS and not peak. And how reflective is their environment? Also, I would expect an audio amplifier company to test amplifier power levels by using a sound meter. They need to connect a "high-quality" power meter into the circuit to establish the output levels.

I still suggest that you approach them about the waveform limiter, and, as I posted before, ask for documented test plans, test specifications and test results.
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/03/07 02:01 PM

So their explanation about the Wave Form Limiter and the resister that controls the input makes no sense to you?

I'm sure they have the best test equipment available as most amp companies do, otherwise, I don't know how they could provide research/engineering/design for other companies.

Thanks
Posted by: Ken.C

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/03/07 02:03 PM

Randy, it would seem that you've already made the decision to keep the amp. So... keep the amp.
Posted by: Mojo

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/03/07 02:07 PM

Quote:

So their explanation about the Wave Form Limiter and the resister that controls the input makes no sense to you?





I understand how the waveform limiter works. I just don't understand why it would shut the amp down. The limiter should simply decrease the amp's gain...not turn it off. BTW, this is very similar to what the EP600 does...it just does it using a DSP.

I am sure Emo have the best equipment. Now let's get them to use it so that they can solve this problem . I'm certainly keen on buying one of their amps in the future so I'd like to see them succeed.
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/03/07 04:02 PM

Thanks everyone for their input, I'm very confused getting feedback from both sides. I just wish you guys could do the talking for me.

I think I'll hit a bar on the way home and have a few Guinness beers and ponder what to do next, arggg. Maybe I'll send it back and get one of the new Denon's with MultEQ from Odyssey.
Posted by: michael_d

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/03/07 04:44 PM

Quote:



They are NOT defective, whatever you think. It has all been explained above. Any amp WILL clip if driven past its limits, I don't care if you have a Rotel or whatever. You say yours did not clip, what facts or equipment do you have to back that statement.





That you asked that question in the pissy-assed tone you used, and actually think a person needs complicated testing equipment to prove clipping is occurring is enough to demonstrate that there is nothing I can do or say to you to explain the obvious to you.

And what really bugs me about your response is that you seamed to forget that YOU posted the question asking for advise, and that YOU posted the problems your are experiencing, and YOU are the one who continues to negate anything that anyone else has posted that does not coincide with what you want to hear. > there is nothing wrong.

I am doing nothing but trying to help you out and possibly anyone else gullible enough to believe that nothing is wrong here. I will not do that again, at least not for you.

I should have learned my lesson trying to make you aware of a potential unsafe grounding situation in your home. – that you chose to ignore as well.
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/03/07 05:03 PM

For starters, your advice is why I had 2 electricians from two companies come out and check our house. They both said there was nothing wrong with the electrical box or ground in my home. It is to code. The problem was resolved by Emotiva by placing a cap on the regulators that operate in the ghz frequencies.

I live close to an airport and the signal tower operates in the microwave frequencies, which was interfering with the amps, they made it right again, and the ground was not to blame.

Your still not providing any facts as to why you think the amps are defective, versus just being pushed to their design limit. 119dB's at 1 watt 1 meter requires 256 watts. If the $49 Radio Shack meter is not as accurate as the Audio Toolbox meter, which I think most would agree, then peaks of 20dB's would refer to ranges beyond 300 RMS, in which the amps protective circuitry would be introduced.

I just need to decide if I can live knowing the amp will shut down if pushed to +4 on the volume knob, or look for something else.

I am not the only one having this problem, if you follow other forums. Otherwise, I would say yes I have a defective amp. Other people with 4ohm speakers from Onix, NHT, and Axiom are having the same issues when pushed to similar levels.

Thanks, anyway.
Posted by: Lorenzo1000

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/03/07 05:19 PM

Randy I am not going to tell you that the amps are defective. To be honest I don't know one way or the other if they are defective or not. The one thing I can tell you is that they do not meet your needs or expectations. That alone should be enough that you would send them back and seek out other products that may be better suited to your listening environment. I think that your Denon is one of the best HDMI receivers out there at the moment so I don't think you need to replace that unless you need more HDMI inputs.

It would be nice if you lived closer so I could lend you my ATI amps to try out to see if there was any difference. Good luck with your decision.
Posted by: Hutzal

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/03/07 05:28 PM

Quote:

The one thing I can tell you is that they do not meet your needs or expectations. That alone should be enough that you would send them back and seek out other products that may be better suited to your listening environment.




well said.
Posted by: Lorenzo1000

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/03/07 06:17 PM

Well apparently I'm none too bright as all along I thought Randy was using the Denon 2807 which has HDMI when he actually has the 2805. Still shouldn't make any difference amplifier wise though.

Thanks for pointing out my faux pas Randy and good luck with whatever you decide to do.
Posted by: bugbitten

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/03/07 07:30 PM

Quote:

Quote:

The one thing I can tell you is that they do not meet your needs or expectations. That alone should be enough that you would send them back and seek out other products that may be better suited to your listening environment.




well said.




Send it back. Try something else with big toroids like the Outlaw 7500 (2 toroids). See if it meets your needs. You can always go back.
Posted by: Wid

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/03/07 07:35 PM


That's one thing the Rotel RB 1080 has, it has a 1.2 KVA transformer.
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/03/07 07:44 PM

How large are the toroids in the Outlaws spread across 5 or 7 channels? I know each amp on the mps-1 has its own 350VA Toroid or 2.45KVA total for 7 amps.
Posted by: Mojo

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/03/07 07:49 PM

Quote:

...which I think most would agree, then peaks of 20dB's would refer to ranges beyond 300 RMS, in which the amps protective circuitry would be introduced.




By protective ciruitry, I am assuming you mean a shut-down circuit. Since EMO is using a waveform limiter, a shut-down circuit should not be necessary. The limiter should attenuate the gain of the amp...not shut it down. Otherwise, what exactly is the point of the limiter?

Quote:

Other people with 4ohm speakers from Onix, NHT, and Axiom are having the same issues when pushed to similar levels.




I am starting to wonder if the resistors EMO used to simulate speakers during power testing changed value as they were being heated. The devil's in the details.

I find statements such as these on the EMO site worthy of further inquiry. I very much doubt EMO is achieving 0.015% THD into 4 and 2 Ohms:

• THD less than .015%, 20Hz-20kHz with 80kHz measurement bandwidth
• 200 watts/8 ohms – 300 watts/4 ohms – 400 watts/2 ohms - seven channels driven, mains limited
• Frequency response 20Hz-20kHz +/- 0.1 dB, or 10Hz-125Khz +/- 3dB

A spec written like this would certainly be less confusing (some of my numbers are made up): Frequency response 20 Hz to 20 KHz +/- 0.1 dB with 0.15% THD for 200W into 8 Ohms, 1% THD for 300W into 4 Ohms, 5% THD for 400W into 2 Ohms.

Having said all of this, for the price, I would certainly be happy with one of these amps .
Posted by: bugbitten

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/03/07 07:53 PM

Quote:

How large are the toroids in the Outlaws spread across 5 or 7 channels? I know each amp on the mps-1 has its own 350VA Toroid or 2.45KVA total for 7 amps.




I'll have to find the size (I bet Gonk knows), but the 7500 and 7700 have the same 2 toroids. Must be big for the 7500 to weigh 80 lbs.
Posted by: Mojo

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/03/07 07:54 PM

I think that's pretty similar to the MPS-1. The MPS-1 toroid looks like 600-700 VA and drives a single channel. The Rotel drives two channels.
Posted by: Mojo

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/03/07 08:00 PM

Quote:

I know each amp on the mps-1 has its own 350VA
Toroid or 2.45KVA total for 7 amps.




Are you sure it's only 350VA? It looks a lot bigger than that. If so, how is it that they are doing 780W RMS? The toroid would burn like my quiche in grade 7 cooking class.
Posted by: bugbitten

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/03/07 08:40 PM

350VA is correct for the MPS.
Posted by: JohnK

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/03/07 10:18 PM

Randy, one of your questions involved possibly disabling the anti-clipping limiter circuit, but as Mojo also pointed out this circuit doesn't cause the amp to shut down, it just lowers the gain. The result is that at extreme levels a lower, more rounded wave top results instead of a clipped flat top. So, that circuit isn't guilty with respect to the shutting down.
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/03/07 10:39 PM

Ok, John, Mojo, and whoever wants to provide input, here goes.

I dug out my old digital multimeter. About 15 years ago I took an electronics class through the NRI schools. About all I can remember is watts = volts x amps, if I recall correctly.

So, how about I hook up the multimeter between the speaker terminals on the amp, and the 12AWG wire going to my m80's. Then watch the current (amp) readings as I slowly turn up the volume while listening to music. If I make note of the reading at the time the amps shut down, could I not figure out the watts, and see if I truely am even close to 300 watts?

I just want to be in the ballpark, so when I call Emotiva I've got a little evidence, other than the Radio Shack SPL readings.

Thanks, Randy
Posted by: JohnK

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/03/07 11:04 PM

Yes, do it, but you'll be reading voltage(which is the boss), not current. Then the form of Ohm's Law which is applicable would be P=Vsquared/R.
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/03/07 11:08 PM

Ok, I'm confused, isn't it current that would be traveling through the speaker wires? And, voltage is what would be in the AC line?

Easy on me John.
Posted by: JohnK

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/03/07 11:15 PM

Randy, the actual power is being carried by way of an electromagnetic wave traveling along the outside(not inside)of the speaker wire. Don't worry about current at this point; the standard way of measuring what you want to learn is by way of taking the voltage across the output terminals at varying levels.
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/03/07 11:17 PM

ok, I'm going to run down and give it a quick try...thanks a bunch
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/03/07 11:30 PM

Since the kids are in bed, I could not turn it up very far as their rooms are right above my HT area.

Anyway, I turned my meter on the 2 Volts selection and attached the black (COM) clip to the negative wire, and the red (volt) clip to the positive wire terminals.

When playing a particular song, obviously the readings bounced around, but the highest I saw it jump was 1.60.

So would this be correct using your equation?

P=Vsquared/R
P=2.56/4
P=.64 watts

Thanks, Randy
Posted by: MadScientist

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/03/07 11:34 PM

Perhaps I can shed a little light here. You will need a stable 4 ohm load bank and not the speakers themselves. Speakers are a reactive device and not a purely resistive load. So you will need a solid resistive load to get an acurate measurement. Next you need to check and make sure your meter is frequency compensated. Most are not. Lastly you will need a CD with test tones on it. Music is all about the dynamics and you will not get an accurete ready.

Connect the load bank to the output of the amp, bring up the volume a test tone, probably something around 1Khz and measure the voltage at the speaker terminals. Then it is just a little math to get the power output.
Posted by: JohnK

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/03/07 11:56 PM

See, I told you that you didn't need all that power! Okay, I was looking for something in the area of 20 volts peak. The suggestion of maybe using a test tone disc at a specific frequency(a few hundred Hz, say)rather than music is a good one. Then the frequency and the level won't vary(except when you vary it), and the specific M80 impedance at that frequency(from the NRC measurements)can be used and should be adequate.
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/04/07 12:03 AM

Thanks, yeah I had to leave it at like -30 on the volume knob, nowhere near the +5 when the amp shuts down. I will do some more testing when I have more time. As you mentioned the m80's are a very stable 4ohm load, unlike many other speakers that are all over the place. For what I'm trying to research this will be adequate. I do have the Realtraps test tones from when I graphed my room acoustics, I may try that as well.

Thanks again, I will keep you posted.
Posted by: Mojo

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/04/07 12:09 AM

Randy,

MadScientist is essentially right. But good luck finding that "stable" load bank. By stable, he means that it can't change resistance as it heats up (I suppose you could rig it up in your freezer ). This is what I mentioned earlier about the testing that Emo is doing.

And he's also right about the speaker not always being 4 Ohms. The impedance changes with frequency. Now how much it changes I don't know. And he's also right about a frequency-compensated meter. So, you could go about this in two ways to get a very gross indication:

1. Put on some pink noise. Avoid a test tone as you could end up over-heating and damaging one of your drivers!!! Ask Axiom to tell you what the impedance of the M80 is with pink noise. I wouldn't be surprised if it's somewhere around 4 Ohms. Set your volt-meter to 60V AC (not DC). Find some way to clamp the leads on to the speaker terminals (DON'T ATTEMPT TO HOLD THE LEADS AS 15 THOUSANDTHS OF AN AMP IS ALL IT TAKES TO KILL YOU!!!). Turn up the EMO and take readings of the voltage. Your power will be E squared over the speaker impedance.

2. If Axiom won't give you the impedance, then you have to measure both the voltage and the current. So you will need two meters set on AC. The voltmeter will go across the terminals as in 1. and the ammeter will go in series with the wires. Set the ammeter to 15 amps. Clamp the ammeter on (DON'T ATTEMPT TO HOLD THE LEADS AS 15 THOUSANDTHS OF AN AMP IS ALL IT TAKES TO KILL YOU!!!). Take both measurements and multiply.

Take SPL readings as well if you can. I have to tell you that I really don't know what kind of accuracy you will get from these measurements as it all depends on the meter characteristics. Remember: DON'T ATTEMPT TO HOLD THE LEADS.
Posted by: MadScientist

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/04/07 12:10 AM

Quote:

Thanks, yeah I had to leave it at like -30 on the volume knob, nowhere near the +5 when the amp shuts down. I will do some more testing when I have more time. As you mentioned the m80's are a very stable 4ohm load, unlike many other speakers that are all over the place. For what I'm trying to research this will be adequate. I do have the Realtraps test tones from when I graphed my room acoustics, I may try that as well.

Thanks again, I will keep you posted.




No matter how stable the impedance is, it is still not a resistive load. The M80 have a complex crossover with both resistive and capacitive elements which will reck havac on your readings.
Posted by: JohnK

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/04/07 12:13 AM

My first impression was that something was wrong with the hookup, but if you were listening at that moderate a level, maybe that was a reasonable result. Using about .64 watt would result in about a 89dB output from the M80 at 1 meter(neglecting room effects), which is comfortably loud. It'll be more interesting when you're able to turn it up into the problem levels.
Posted by: MadScientist

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/04/07 12:19 AM

Mojo, Good suggestion. Measuring the voltage and the current would give a reasonably close measurement.

The only variable not accounted for is distortion. I would recommend that you use a Piezo tweeter wired across the speaker terminals of the amp. Play a tone that is well below the frequecy response of the tweeter (like 100hz). Turn up the volume until you hear a buzzing in the tweeter. The buzzing you hear is the harmonics generated by the amplifier clipping and squaring off. Then you could take your measurements and run the math.
Posted by: Mojo

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/04/07 12:33 AM

The piezo tweeter is actually a very good idea. So he would disconnect his speakers and connect the piezo tweeter, apply the low frequency tone, turn up the gain until the piezo starts shrieking, remove the piezo, connect the M80s and measure.

What kind of a load does the piezo present to the amp?
Posted by: MadScientist

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/04/07 12:37 AM

Somewhere in the neighborhood of 2Kohms at low frequencies. So you would really need to apply some other kind of load to the amp like a passive sub. Otherwise the amp wouldn't be loaded properly. With such a light load the power supply rails would not sag.
Posted by: bugbitten

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/04/07 10:10 AM

Quote:

Quote:

How large are the toroids in the Outlaws spread across 5 or 7 channels? I know each amp on the mps-1 has its own 350VA Toroid or 2.45KVA total for 7 amps.




I'll have to find the size (I bet Gonk knows), but the 7500 and 7700 have the same 2 toroids. Must be big for the 7500 to weigh 80 lbs.




I still haven't found the sizes but Gonk has photos:

http://www.prillaman.net/outlaw_pics/ (about halfway down)
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/04/07 10:24 AM

Seems pretty stable in the lower freq's. Guys, I don't have two meters, just the one. So your telling me what I was doing last night, won't even get me in the ballpark?

Mojo, if I do your pink noise test and find out from axiom the ohms with pink noise will that work? How does this account for dynamic peaks during songs?


Posted by: Wid

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/04/07 10:51 AM

From the Outlaw Manual.

Your new power amplifier is a state of the art, high performance, audio
component. It is built utilizing totally complementary circuitry from input to
output. The high current power supply is driven by custom-designed torrodial
transformers (Model 7200 @ 2.0 KVA / Model 7125 @ 1.6 KVA / Model 7075 @
800 VA) with two separate windings for each of the seven channels. The per
channel filter capacitance of the Model 7200 is 22,600 uF, while Model 7125
measures 20,000 uF, and the Model 7075 comes in at 16,400 uF. All seven
channels are each protected by an advanced Opto-coupled protection circuit.
Heat management is provided by custom-designed heatsinks on each amplifier
module, enabling the amplifier to function at full power without the need
for noisy fans.


Randy,

What is the point of trying to measure the output at this point? It seems to me it would be tough keeping the amp knowing its shortcomings.
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/04/07 11:05 AM

True Wid, it would just make me feal better. I can then have some factual numbers to back my discusions versus saying, others on my website think something is wrong.
Posted by: Wid

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/04/07 12:18 PM

Quote:

others on my website think something is wrong




Well there is some news Yeah something is wrong, those amps are not what they are cracked up to be. It seems an ol boy over at AV123 did snip off the resistor you were talking about and the amp is still shutting down.........that sure as heck isn't good.
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/04/07 12:35 PM

Yep, he just disabled his wave form.
Posted by: real80sman

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/04/07 01:06 PM

Randy, I read through the whole thread and by the time I got to the end, I forgot half of what I read......

So, is or is not the EMO delivering it's claimed output without shutting down? That's the only question that really matters. If it only shuts down once you push past this point, than nothing is wrong. The protection circuit is doing what it's supposed to, and the guys at Emotiva have done their job. If it's not delivering the rated power, then they have more work to do.

If it is delivering the goods, and if you'll be pushing past this point on a regular basis, send it back - you need a bigger amp, man.

It would be nice if Ian or Alan would chime in on how the Sherwood amp performed during their torture tests with the 80's.
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/04/07 02:39 PM

According to them it is, but they are not testing with 80's. I'm now starting to wonder, based on what I'm hearing elsewhere from others.

Based on my findings, I'm only using about 10 watts from 12ft away to achieve 100dB's, the amps are shutting down at 106-7dB's. Now I'm no expert like some of these other guys, but you can't tell me I'm using all 300 watts.
Posted by: MadScientist

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/04/07 03:15 PM

sirquak why don't you just ask them to send you the AP graphs for the THD and Power output. That will show exactly how much power it is producing. Any company worth its salt uses an AP for its testing so they should have the graphs.
Posted by: michael_d

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/04/07 03:53 PM

Quote:


So, is or is not the EMO delivering it's claimed output without shutting down? That's the only question that really matters. If it only shuts down once you push past this point, than nothing is wrong. The protection circuit is doing what it's supposed to, and the guys at Emotiva have done their job. If it's not delivering the rated power, then they have more work to do.





The point in contention is why these amps are shutting down. It does not matter one bit if they are putting out 50 WPC or 700 WPC. They are shutting down.

If they are putting out more power than advertised or what they are rated at, then Emo needs to integrate current limiting circuitry and not rely on over current protection as the current governing device.

Over current protection is a safety feature that should not ever come into play unless there is a short to ground somewhere on the load side, or if the amp is driving a load that it is not rated to drive. However, it is not driving a load it is not rated to drive, and there is no evidence to support a short to ground scenario (this is usually identified with cool lights, flashes and smoke).

Something is most definitely wrong. Specifically; the design.

Think of it this way.

Next time you get into your car, leave it in first gear and then pin the throttle down and see what happens (long straight away lacking of traffic and pedestrians please). Unless it’s an older vehicle with an older drive train that does not have a computer management system, it will reach red line RPM and the engine will not spin any higher or drive the car any faster. IT DOES NOT JUST SHUT DOWN. …….and neither should your amplifier.
Posted by: Mojo

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/04/07 04:04 PM

I agree with mdrew although I won't go as far as to say this is a design issue. It could be a manufacturing issue. We just don't know.

MadScientist's graph suggestion is a good idea but it's impossible to understand the graphs without understanding the test procedure and equipment used. And this is where things get very complicated and require careful study.

For what it's worth, here is the performance that I am experiencing with my M80s in my very bright, 4000 cubic foot space. The voltage is measured with a $30, analog meter from radio shack that has no specs whatsoever. I am confident SPL is accurate to within +/- 1 dB for this frequency. I only went up to -10 on my amp's gain because I was worried about damaging a driver.

Both channel levels are set to 0, left channel RMS voltage measured with a 1 KHz tone (the test CD says that this is a 0dB tone; all other tones on the CD are -10dB). SPL is C-weighted, slow with two channels from 12 feet away. The impedance (Ohms) was taken from the Axiom graph that Randy posted. Power is in watts for my left channel. The power for both channels is of course double the power for a single channel. My Denon amp is rated 90WRMS + 90WRMS for 8 Ohms with 0.08% THD (over audible frequency range) and 125WRMS + 125WRMS for 6 Ohms with 0.7% THD at 1 KHz. No rating is given for 4 Ohms. Based on the 1 KHz input frequency, the M80s are operating at 8 Ohms.

amp.....Vac.....Z......Power.....SPL
-30......0.9....8.5......0.1.........75
-20..... 2.5....8.5......0.7.........84
-10..... 9.5....8.5......11..........92

I haven't spent any time interpreting these results to understand if they "make sense" or how the apply to Randy's situation. Comments from anyone?
Posted by: MadScientist

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/04/07 04:38 PM

Quote:

Randy, I read through the whole thread and by the time I got to the end, I forgot half of what I read......

So, is or is not the EMO delivering it's claimed output without shutting down? That's the only question that really matters. If it only shuts down once you push past this point, than nothing is wrong. The protection circuit is doing what it's supposed to, and the guys at Emotiva have done their job. If it's not delivering the rated power, then they have more work to do.

If it is delivering the goods, and if you'll be pushing past this point on a regular basis, send it back - you need a bigger amp, man.

It would be nice if Ian or Alan would chime in on how the Sherwood amp performed during their torture tests with the 80's.




I supose it is a matter of personal preferrence, but I agree with 80sman here. If the amps do what they state before shutting down, then the only problem is you need an amp with more power rather than the amps being flawed.
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/04/07 04:41 PM

Here is Dan's response to me on AV123....

Dear Randy,
I know that Lonnie has explained the situation to you with respect to amplifier protection thresholds into 4 ohm loads. I would like to reiterate for all MPS-1 owners, if I may.

Let me be perfectly clear; the amplifier will not inhibit into 3-4 ohm loads unless the soft limiter is sensing significant levels of distortion. It doesn't shut the amplifier down "for no good reason". If you are driving your amplifier into a four ohm load and it inhibits, it is because the soft limiter has been driven to the point it sees you have exceed a preset output volt/amp threshold that we have set. Under these circumstances, the amplifier is being driven into pretty hard clip. You don't hear it as such because the soft limiter is doing its job. It is reducing the hard edge clipped waveform into something more benign. But, when you listen to the amplifier under this condition, you can clearly hear the change as the amplifier sound appears to soften and dynamics are affected. This is intentional and was designed to keep you and your speakers safe and sound. Our goal was to make a better product; for some people, this is seen as a negative attribute. One reviewer thought the amplifier didn't make enough power; we explained to him our thinking behind the limiter and he didn't get it. He felt is made the amplifier seem less potent than it really is. Our desire to build a cool feature into the amp may have backfired on us with some people. I guess you can't please everyone!

To address your comments about SPL's measurements and your displeasure over only being able to reach SPL's in the low 100+dB range at 12 feet in your room, as measured by your RS meter; this is not a scientific method of determining real power output. The RS meter is not a peak reading meter and its VU metering ballistics are suspect. Your measurements are low by at least 6-10dB. Also, at 100+ dB the microphone in the in the meter is compressing which adds to measurement errors. The problems with this test methodology go on and on.

Also, hanging a DVM across the speakers while playing music is not going to provide meaningful data either. I don't want to go into a long technical dissertation as to the problems with this measurement technique, but please trust me, your approach is not correct.

We have given you a solution for the address your unhappiness with the protect threshold which involves removing the soft limiter. This will make the MPS-1 behave exactly like the IPS-1 and and LPA-1 amplifiers.
It will not make the amplifier bad or dangerous to your speakers. It will will make the amplifier behave like 99%of all other all other amps on the market. You will only have hard clipping present on the amplifier output when you push it beyond its power ratings. You may find that you hear the sounds of distress more readily this way as the soft limiter will not cover up this over load condition. At then end of the day, it is up to the judgment of the listener to exercise common sense when we hears obvious signs of distress in his system.

In any event, it will eliminate you major complaint. The unit will still be under warranty, all normal protect functions are still in place, and if you are not happy, we will return your module to its original state for you free of charge.

I suggest you try it on your main left and right modules and see what you think! You may be very pleased with the outcome; and you have nothing to lose!

I hope this helps clarify our recommendations and the thinking behind our decisions. Please let us know if this addresses your problem. I'm sure many other people would like to hear your feedback on this issue. As always, feel free to contact us with any other questions or issues you may have.

Thanks for your support.
Best regards,
Dan
__________________
Dan Laufman
President
Emotiva Audio Coporation

Posted by: Mojo

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/04/07 06:29 PM

Quote:

Let me be perfectly clear; the amplifier will not inhibit into 3-4 ohm loads unless the soft limiter is sensing significant levels of distortion. It doesn't shut the amplifier down "for no good reason". If you are driving your amplifier into a four ohm load and it inhibits, it is because the soft limiter has been driven to the point it sees you have exceed a preset output volt/amp threshold that we have set. Under these circumstances, the amplifier is being driven into pretty hard clip. You don't hear it as such because the soft limiter is doing its job. It is reducing the hard edge clipped waveform into something more benign. But, when you listen to the amplifier under this condition, you can clearly hear the change as the amplifier sound appears to soften and dynamics are affected. This is intentional and was designed to keep you and your speakers safe and sound. Our goal was to make a better product; for some people, this is seen as a negative attribute. One reviewer thought the amplifier didn't make enough power; we explained to him our thinking behind the limiter and he didn't get it. He felt is made the amplifier seem less potent than it really is. Our desire to build a cool feature into the amp may have backfired on us with some people. I guess you can't please everyone!




This is not how a waveform limiter works. A waveform limiter reduces the gain in order to maintain stability. It does not at all affect dynamics. From the description above, Emo does not employ a waveform limiter but rather a soft clipper...hence the effect on reduced dynamics as the peaks get soft-clipped. And I understand the struggle they have with such a feature. They should have made this feature configurable and provided a very well-written description in their manual. I guess this is an opportunity for improvement. Frankly, I don't think the designers implemented what the product champion(s) originally envisioned and the champions are finding out now at a late stage.

Quote:

To address your comments about SPL's measurements and your displeasure over only being able to reach SPL's in the low 100+dB range at 12 feet in your room, as measured by your RS meter; this is not a scientific method of determining real power output. The RS meter is not a peak reading meter and its VU metering ballistics are suspect. Your measurements are low by at least 6-10dB. Also, at 100+ dB the microphone in the in the meter is compressing which adds to measurement errors. The problems with this test methodology go on and on.

Also, hanging a DVM across the speakers while playing music is not going to provide meaningful data either. I don't want to go into a long technical dissertation as to the problems with this measurement technique, but please trust me, your approach is not correct.




I don't disagree with the underlying message which is "Be aware of the inherent limitations of your measuring set-up and apparatus". I don't have a RS meter but I do have full confidence in my SPL meter to within a dB for frequencies between 200 Hz to 8 KHz and up to 125 dB. I have this confidence because I have verified a number of frequencies within this range and SPL against my buddy's $1.5K SPL meter. And yes, he's also right about the DVM as we've previously discussed. Randy, you have more work to do in this regard (should you choose to walk down this scary path ). In my mind, the verdict is still out as to whether or not you are sourcing 300W from the amp. But, look at the facts to date. You are telling us that you are achieving 100 dB with 10W. Look at what I posted. Granted, our rooms are different and I used a test tone and your RS meter may be wrong (which it might be but I would bet only by a dB). But, it's a place to start. If I had to put money down right now, I'd say you are nowhere close to 300W when you are shutting down at 106 dB.

Quote:

In any event, it will eliminate you major complaint.




Will it? I thought other listeners are experiencing shut-down with the clipper removed. They could be playing at absolutely ridiculous levels and over-heating the unit.

BTW, I still don't understand how they claim to be sourcing 700WRMS on the output with a 350VA toroid.
Posted by: Mojo

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/04/07 07:41 PM

Updated measurements at 0 and +10:

amp.....Vac.....Z......Power.....SPL
-30......0.9....8.5......0.1.........75
-20..... 2.5....8.5......0.7.........84
-10..... 9.5....8.5......11..........92
..0.......30.....8.5......106.........95
+10......37.....???......???.........???

At 0, I still had what sounded to me like a pure tone. At +10, my amp was distorting badly. It's hard to say what frequencies exactly were going into the speaker. So it's meaningless to attempt to do any calculations with the gain at +10.
Posted by: real80sman

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/04/07 08:20 PM

mdrew, thanks for the clarification. I can only rely on my own experience with the 80's. I've driven them with a late 1980's Luxman 2ch integrated amp, and an early 2000's Yamaha 6.1 receiver.

With the Luxman, as I turned it up it would really sing. It stayed clean and controlled. Sounded awesome. Push it a little more and 'click' - off it went. Turn it back down, and within 10 seconds it was back on. It was NOT rated for 4ohms and when pushed, ran super hot. (Currently, it's driving my M3's in the office.)

With the Yamaha, when it's pushed things get nasty. The highs sound raw and really rough, and the bass is distorted. I've gotten it up to -8db, and I thought "Why?". I usually run it around -20db which is plenty loud enough for movies. (Lower when the family is around) But for music, at the levels I like to listen to, I NEED more power. (The area is ~12,000cuft) For most day to day listening, I'm happy with the Yamaha. It sounds great so long as it isn't pushed hard.

As a side note, the Yammy runs fairly warm, but has never shut down.


Posted by: bugbitten

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/04/07 09:36 PM

Quote:

Quote:

Quote:

How large are the toroids in the Outlaws spread across 5 or 7 channels? I know each amp on the mps-1 has its own 350VA Toroid or 2.45KVA total for 7 amps.




I'll have to find the size (I bet Gonk knows), but the 7500 and 7700 have the same 2 toroids. Must be big for the 7500 to weigh 80 lbs.




I still haven't found the sizes but Gonk has photos:

http://www.prillaman.net/outlaw_pics/ (about halfway down)




This from Scott at Outlaw:

Quote:

Transformer power ratings can vary dramatically because of a lack of standards in our industry. The "duty cycle" is what determines the VA rating because temperature rise has to be controlled. If you had a battery charger, the transformer has to handle 100% duty cycle because the power is delivered constantly. Not so in the case of audio power amplifiers. The duty cycle is less than 50% for music and even lower for most home theater applications. All transformers in Outlaw amplifiers can deliver whatever power is demanded by the loudspeaker load without fear of overheating or damage. For a home theater applications, because of the lower duty cycle, the transformers in these amplifiers could theoretically handle 4 thousand VA without overheating. Even though this is true, we use a much more conservative approach.


For the record, both the 7500 and the 7700 meet (actually exceed) their power ratings of 200 Watt per channel-all channels driven at .05% from 20 - 20 kHz (unlike some other manufacturers, we are not rating our amps at 1 kHz or are measuring our power at 1% distortion.)


Each of these amplifiers utilizes two transformers of varying "sizes" depending on how many channels they are asked to drive. Each transformer has a number (either two, three or four) of secondary windings so that each winding is dedicated to its' own channel. By our calculations, the 7500 transformers have a total of approximately 1.8kVa and the 7700 has about 2.05kVa.

Scott



Posted by: JohnK

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/04/07 10:11 PM

Randy, give the multimeter voltage measurements a try at the shut-down levels. Yes, it isn't the way that amplifier output is measured professionally; among other things fixed resistance into a set of resistors is used(rather than a speaker), the frequency is known, rather than variable as it is with music, and an oscilloscope is used to observe the point at which the wave form top flattens, indicating clipping. However, this "quick-and-dirty" measurement is often used to get a ball park number. Don't worry about refinements at this point; it'd be interesting to see the voltage numbers at very high sound levels.
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/04/07 10:16 PM

Hold your horses, almost done John....
Posted by: KlipschGuy

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/05/07 11:25 AM

hey Shawn , I agree about your findings. I also read here some where that Alan was having an Axiom party and had the M80's cranked pretty good with Dennon amps and guess what? They shut down! I think Axiom could speak up and let us know their thoughts on this issue, these speakers do seem to be more difficult to drive than is first seen, however, they sound awesome!

Chris
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/05/07 12:17 PM

The 80's have been able to handle over 1,000 watts in lab tests for extended periods of times, as well as other tests where they ran them at 700 watts continuous for weeks at a time. A Denon AVR of 100 watts (more like 80) is far different than an amp rated at a tru 200 watts into 8ohms.
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/05/07 12:35 PM

Ok, here are my findings. Please note - I'm not an engineer and don't have expensive equipment. Hopefully these results will at least give a clearer picture. I understand that my SPL meter is not the same as say using an expensive faster/more accurate meter like an audio toolbox.

With some help from Mojo I wanted to verify the accuracy of my meter. So, I took my digital multimeter which measures AC voltage up to 1000V. I verified that I was getting 120 volts from my wall outlets (actually 122). So we would have a voltage of 60hz at the outlet. I then played a 60hz WAV tone (2mb filesize) and took measurements with my meter hooked to the speaker wire terminals from various volume levels to compute power. We know the ohm ratings of the 80's per the graphs from the NRC, so I'm off to the races.

Now I also made note of when I noticed distortion starting to kick in, as the results would then become less meaningful. Following this, I ran a 100hz tone, assuming it would be fairly accurate at this freq also as it was close to 60hz. And finally, I played some music.

Below are my results from my lab. It appears based on my defense above, that the amp is not defective, and functioning as designed. Again, you guys need to remember I'm trying to fill 8,000 cubic feet. Plus, I've acoustically treated my room pretty well with OC703 which is actually helping the potential problem of rooms that have no treatments.

Also, if you look at the music peaks before it shut down, and the 100hz tone(which is easier to drive than higher freq's) the amp actually went beyond its ratings.
I will need to work with Emotiva to discuss my options.


Volume Knob, Voltage, P=Vsquared/5 60hz tone

-25, .64, .08
-20, 1.11, .24
-15, 1.99, .79
-10, 3.40, 2.31
-5, 6.08, 7.39
0, 10.75, 23
+2, 13.48, 36
+4, 16.85, 56.7
+5, 18.8, 70.5
+6, 21.1, 89
+8, 26.2, 137 (buzzing/distortion started)
+10, 33, 218
+12, 36.7, 269
+13, 38.5, 296 (clicking sound, amp shut down)


Volume Knob, Voltage, P=Vsquared/4 100hz tone
-25, .64, .1
-20, 1.11, .3
-15, 1.99, .99
-10, 3.40, 2.89
-5, 6.03, 9.09
0, 10.67, 28.46
+2, 13.36, 44.62
+4, 16.71, 69.8
+5, 18.69, 87.3
+6, 20.9, 109.2
+8, 26.2, 171.6
+10, 33, 272
+12, 36.7, 336 (Buzzing/distortion started)
+13, 40, 400 (clicking sound, amp shut down)

Music Listening - I picked 2 songs from my brother inlaws band "Left is West" which

is a very popular Des Moines based band that I would put up against any of the

bigger city bands. Their CD was recorded last year in Omaha by Barely Bias Label. I

would describe them as pop-rock with similar influences from bands from the 70's to

today, just a whole mishmash. Anyway, I picked 2 songs that had a very fast

rock beat that didn't change or fluctuate much, just very intense and powerful.

I used 4 ohm for figuring power, the results would be slightly lower had I used say

4.5-5 ohms for an average. Both songs had similar results except for the last

reading.

Volume Knob, Voltage, P=Vsquared/4 Music
-20, 2, 1
-15, 3.3, 2.7
-10, 6.1, 9.3
-5, 13.3, 44.2
0, 19.8, 98
+2, 24.5, 150
+3, 28.8, 207
+4, 40-50, 400-625
Posted by: PeterChenoweth

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/05/07 02:52 PM

Fascinating results. Glad to hear the amp might not be the problem, and that you're just running into the laws of physics. As in Jaws, "We're going to need a bigger amp".

Have you tried bi-amping your M80's? I wonder if that would get you an extra db or two before the amp shuts down. Might be enough to satisfy your needs, and I would then bow to your awesomeness of having M80's driven by four EPM-300's.
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/05/07 02:57 PM

That I have not, hmmm, it would require me to purchase two more amps to accomplish.
Posted by: MarkSJohnson

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/05/07 02:59 PM

Than just bi-wire!
Posted by: PeterChenoweth

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/05/07 03:02 PM

Quote:

That I have not, hmmm, it would require me to purchase two more amps to accomplish.




I know you said you've been trading amps with Emotiva, so I wondered if maybe you still had a pair of EMP's that hadn't been shipped back yet .

That MPS chassis has the room; c'mon man, doo eet!

It is only money.

Just let me know if/when you ever test this. I'll keep an eye on my line voltage. Since we're only a few hundred miles apart, I bet you'll dim the lights at my house when you test it.
Posted by: KlipschGuy

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/05/07 03:04 PM

I was thinking of the same thing,you could use the center amp on one main channel and see what happens?
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/05/07 03:07 PM

Your right, I shipped 2 back last friday. So I assume you have to get a splitter cable of some sorts since my Denon only has one preout per channel?

I don't know Peter, I'm just getting tired of messing with this thing. First the light switch static issue when I first purchased it, now this issue. I just want to enjoy my equipment.
Posted by: MarkSJohnson

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/05/07 03:09 PM

Quote:

I just want to enjoy my equipment.




(This page intentionally left blank)
Posted by: PeterChenoweth

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/05/07 03:17 PM

Correct (I think) . You'd need a splitter for each channel.

Too bad you're not just a wee bit closer to where I live, I'd bring over the LPA-1 just for fun to see how it performs. I still haven't officially tested my LPA-1 w/ db meter to see if I can 'max-out' my system. But I know that -5 (max is +15, I think) equates to absurd volume levels on my M80+LPA-1 combo with no distortion and no shut-down problems. I mean, worried-about-my-hearing, cat-runs-and-hides, pictures-fall-off-walls loud.

I do hope you find a workable solution. It just seems very odd that your measurements appear to indicate the amp is working as advertised, and the M80's most certainly aren't bad, but you're still having these shutdown problems.

Quote:

Your right, I shipped 2 back last friday. So I assume you have to get a splitter cable of some sorts since my Denon only has one preout per channel?

I don't know Peter, I'm just getting tired of messing with this thing. First the light switch static issue when I first purchased it, now this issue. I just want to enjoy my equipment.



Posted by: Mojo

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/05/07 03:23 PM

Randy,

A couple of things:

1. I'd ask Emo to comment on the distortion. See what they have to say.

2. How did the songs sound to you at increased power levels?

Also, it is more difficult for an amp to amplify lows than highs (you had that backwards in your post).

I suppose Emo has been vindicated through all of this. I think you may be ready to enjoy the Emo now .
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/05/07 03:26 PM

Waiting for a call back from Emo.

2) At +3 the music sounded outstanding with no hint of strain, at +4 shutdown time.
Posted by: Mojo

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/05/07 03:55 PM

Quote:

Waiting for a call back from Emo.

2) At +3 the music sounded outstanding with no hint of strain, at +4 shutdown time.




Oh boy! I didn't realize that it shut down. I can see your predicament now. You had 200W going great with 100W of headroom to spare. The problem is, you can't make use of that 100W given the resolution of your Denon's gain knob. Ouch! Maybe the speaker is closer to 3 Ohms or slightly less during your song sessions. How about turning the channel gain (not the main volume but the individual channel) up 0.5 dB. That might get you what you need.

It sounds like another great feature on the Emo would be a gain trim. This would be a control that would allow you to adjust the gain very finely.
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/05/07 04:43 PM

Same tests using the Denon instead, side by side to MPS-1. The Denon is rated at 100watts into 8ohms.

Volume Knob, Voltage, P=Vsquared/5 60hz tone
MPS-1______________________Denon
-25 .64 .08________________-25 .71 .1
-20 1.11 .24_______________-20 1.25 .31
-15 1.99 .79_______________-15 2.23 1
-10 3.40 2.31______________-10 3.84 2.95
-5 6.08 7.39_______________-5 6.85 9.38
0 10.75 23_________________0 12.18 29.6
+2 13.48 36________________+2 15.2 46.2
+4 16.85 56.7______________+4 19 72.2
+5 18.8 70.5_______________+5 21.3 90.7 (Den 5.5 buzz)
+6 21.1 89 (Emo 6.5 buzz)__+6 23.7 112
+8 26.2 137________________+8 25 125
+10 33 218_________________+10 26.4 139
+12 36.7 269_______________+12 28.3 160
+13 38.5 296(Emo Shutdown__+13 29.6 175 (ranout of volume knob as m80's are calibrated to +5 max vol is +18)


Volume Knob, Voltage, P=Vsquared/4 100hz tone
MPS1_______________________Denon
-25 .64 .1_________________-25 .7 .1
-20 1.11 .3________________-20 1.22 .37
-15 1.99 1_________________-15 2.19 1.2
-10 3.4 2.9________________-10 3.77 3.55
-5 6.03 9.1________________-5 6.72 11.3
0 10.67 28.5_______________0 11.89 35.3
+2 13.36 44.6______________+2 14.9 55.5
+4 16.7 69.8_______________+4 18.6 86.5
+5 18.69 87.3______________+5 20 100 (5.5 Den buzz start)
+6 20.9 109.2______________+6 20.8 108
+8 26.2 171.6______________+8 22.2 123
+10 33 272_________________+10 23.4 136.8
+12 36.7 336(Emo Buzz)_____+12 26.3 173
+13 40 400 (amp shutdown)__+13 27.6 190


Volume Knob, Voltage, P=Vsquared/4 Music
MPS-1______________________Denon
-20 2 1____________________-20 2 1
-15 3.3 2.7________________-15 4 4
-10 6.1 9.3________________-10 6.7 11.2
-5 13.3 44.2_______________-5 13 42
0 19.8 98__________________0 20.8 108
+2 24.5 150________________+2 26 169
+3 28.8 207________________+3 29.6 219
+4 40 400 (shutdown)_______+4 36 324
___________________________+6 44 484 ( I could have kept going but didn't
Posted by: Mojo

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/05/07 04:50 PM

Really? The Denon was going over 300W with music? What did it sound like?
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/05/07 04:55 PM

I was off to the side monitoring the meter and volume control so could not get the same experience as in the main seat. I could tell it was a little strained and not as detailed, maybe you could describe it as a little harsh. But no signs of shutting down.
Posted by: Mojo

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/05/07 05:23 PM

At those kinds of levels, I wonder at what point the Denon would shut down due to over-heating. Maybe you don't need another amp then...maybe the Denon is just fine.
Posted by: Haoleb

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/05/07 07:25 PM

After reading your test results I decided to try out my new true rms fluke DMM, Its got a min/max record feature and i couldnt find my test tones so i just cranked some music. I only got to 30v before i felt i had enough. I would never listen to music that loud simply because its no longer enjoyable. I'm not sure I wouldnt want to play music at that level for hours on end because I doubt that my amps can dissipate the heat fast enough without the help of fans.

Class A/AB amps generate a little more heat than these Class H types
Posted by: Wid

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/05/07 07:31 PM

So are you saying your Denon was putting out 484 watts on music? Somehow I think this is flawed, I don't know how but damn, 484 out of a reciever.
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/05/07 10:01 PM

Wid, not sure how to respond. Keep in mind at any given volume level the meter was fluctuating voltage numbers very quickly. I was watching the display and trying to right down the highest number I noticed.

So lets say during the heavy passages of a song, I might see voltage readings from 10-15.9 and everything inbetween. I then wrote down the highest value I viewed on the display, so the highest peak voltage at each volume selected. I wish my meter had a setting to store the highest value so you don't have to be so alert.
Posted by: KlipschGuy

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/06/07 10:57 AM

LMAO, as if your Denon is even close to putting out 484 watts, lol. Randy, leave the physics to the engineers and just enjoy your system before you DO fry your speakers, those tweeters do not take kindly to the kind of abuse you are putting them through running that Dennon with all that distortion and thats all you're hearing in volume.

Next thread, Help! I have blown tweeters.
Posted by: KlipschGuy

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/06/07 11:30 AM

Ok, I have to add my experience so far with the MPS1. Last night I played the following CD's in full length cranked loud and I mean really friggin loud in my HT which is about 2800 cu.ft.

Dire Straits "Brothers in arms" / huge dynamic peaks
Keb Mo " Simple Things" /massive bass
Poncho Sanchez "15 of his best" again, dynamics that just scream.
UB40 "Homegrown" DVD Concert..woot!,,,,mega, mega , mega bass
Nora Jones (as much as I could handle:) )

Unit got warm, but no where near hot, fans running full steam ahead though. Sound was excellent with zero distortion except for my ventilation rattling. Not one shutdown. I did not use an SPL meter as it doesn't matter what the dial says, my ears said thats friggin loud and I like it loud.

Of course I can make it shut down if I just turn it up till the volume is at insane levels that I would NEVER listen to.

Chris
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/06/07 11:48 AM

thanks chris
apples notequal organges
2800cuft notequal 8,000+cuft
Posted by: KlipschGuy

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/06/07 11:51 AM

This is very true Randy, I was just stating my experience. I think you just need more HP or a smaller room.
Posted by: Mojo

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/06/07 12:32 PM

In response to KlipschGuy (BTW, change the name please. Would you like me to ask Amie to change it for you? ), taking measurements this way is definitely heading down a questionable path...especially music. The problem of course is as Randy plays music, we have no idea what the frequency is and hence the impedance of the speaker.

And KlipschGuy is definitely right. There is a risk in frying the tweeters so I am sure Randy kept the duty cycle of the blaring short.
Posted by: tomtuttle

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/09/07 01:08 PM

Randy, are you enjoying this? It kind of seems not.

I am not an engineer. But it just seems like you've reached the design limits of your equipment in your environment.

Like KG said, bigger amp, smaller room, or live within your very well documented limitations.

It's supposed to be fun, you know.
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/09/07 01:11 PM

You got that right Tom.
Posted by: dlaufman

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/10/07 11:17 PM

Dear Randy,

We've been testing the EPM-300 modules and we do not see any design issues with this amplifier. We have been producing this model for over three years without incident.

When we first heard of your problem, we honestly thought that there might be a real issue. We extensively tested many units and we were only able to make the amplifier shut down when driven to a true overload condition. I must also say that when this occurred the amplifier was in HARD clip.

We have told you in our phone conversations and direct email communication, your testing techniques are not really valid from an engineering, test, and measurement standpoint. Also, all they really seem to do is add more confusion to a fairly straight forward situation.

The problem you are having is that you are asking the amplifier to deliver output power levels well in excess of its rated power. When you do this you are forcing the amplifier into hard clip. It then shuts down. When we asked you to disable the soft limiter, we felt certain that you would be able to hear the difference in sound quality, as the limiter is no longer softening the clipped waveform. It also makes it seem a little "louder". Your response was that you could still make it shut down at "14", whatever that is.

This is what it is designed to do. It is designed to protect itself from gross overload.

I'm sorry that you are not satisfied with the output level you are achieving with this amplifier, but it is not a fault in the amplifier. It is making more than its rated power, and to reiterate, there is nothing wrong with the MPS-1.

The sad thing is that this thread and the associated comments are making people doubt a product that we have produced for a number of years. We have never had complaints of this nature until this last week or so. In both of these instances, it appears the amplifiers are being driven in a manner outside of their design limits.

They are dong EXACTLY what they were designed to do. Some users do not notice hard clipping or signs of overload, these protection circuits are designed to protect both the amplifier and the speaker.

We take great pride in our products and we want you to be 100% satisfied with your unit. As we have told you many times in the past, if you wish to return the unit, please asked for an RMA and we will arrange this for you immediately. You will be give a prompt refund.

Randy, you need at least twice the power of the MPS-1 in order to realize a meaningful increase in SPL. I have no idea why you want to drive your system to these levels but this is your decision. Please use hearing protection; BTW, I'm not kidding!

Respectfully,
Dan
Posted by: pmbuko

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/10/07 11:54 PM

Sirquack,

It seems to me, given your recent findings and the detailed response from Emotiva, that your amps are not flawed. The RS meter is at fault for leading you to believe they weren't playing as loudl as they were when they were shutting down.

You can relax, take out the earplugs, and enjoy.
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/11/07 12:33 AM

Dan,

Thank you for replying. I am a little puzzled as to a few things you mentioned.

First of all, if anything, I have been supporting your product on AVSforum, AV123, and this forum. While others were saying it was defective, I have been trying to work with Lonnie to understand what might be happening, and hoping it was something simple. I have nothing but the highest respect for our company, Lonnie, Kathy, Robert, and yourself.

A little history without going into to many details. First of all I had the issue with static when I first purchased the unit. I spent weeks ruling out my home environement, wiring, speakers, grouding, etc. In the end, this was resolved by Lonnie placing a "cap" on the voltage regulators. I appreciate his quick support and troubleshooting.

This current issue is not unique to me, as other Axiom and Onix owners are having the same issue with 4 ohm speakers and at lower dB levels.

In regards to the R12 resister, I never performed this procedure, as the Ref 1 owner on AV123 already prooved this did not resolve his issues and reporting back to Lonnie. When I talked to Lonnie, he was amazed this did not help the problem, so I have decided not to make this modification.

In regards to my testing, yes I realize it is not up to par with "lab" quality equipment, however, even Lonnie said he was impressed with the results. If anything, my results back what your saying about the amp reaching its limits as designed, have you reviewed them?

I'm not sure what your referring to when you say I said it still shuts down at "14"? I don't recall every making such a statement. The amps shut down at +3 to +4 on the Denon dial, which goes to +18 total. At 0 (zero) on the dial I'm getting 100dB's from 12 ft away, which in an 8,000 cubic feet plus room, is not as loud as you think. Also, keep in mind the m80's are rated 95dB inroom 1 watt 1 meter. All I have to do is click the volume knob 3-4 more clicks above zero and that is all it takes to shut them down, and it is not to insane levels as you might think.

It appears that you think I'm trying to spread negative rumors about your product line, this could not be further from the truth. I'm sorry you see it that way. Perhaps you have not read all of my posts on this and other forums supporting Emotiva and the experts that answer the phone at your location.

One last thing, I have never hinted that I'm having difficulty returning the amp. I really was hoping it would not come to that. If you talk to Lonnie you will understand this has always been in our discussions as an option and have left 2 messages for him to call me.

I'm sorry I even started this thread.
Posted by: bhull

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/11/07 03:53 AM

I actually learned a lot from this thread, so I for one am glad you started it.

I just today broke in my LPA-1 on my new M80s. Had some shutdown problems which was traced to some loose speaker terminals. After that, I gave it a real workout. Had the LMC/LPA at maximum level for about an hour (had a few beers in me ), was watching action scenes in the Matrix and EpIII. Then it shut down. I walked over and put my hand on the top, boy it was hot as hell! So I figured the thermal limiter had kicked in. I don't know the SPLs I was running, but I could sense my hearing distorting...if you wanted to say something to me, you would have to of shouted in my ear...and I might have heard it. I wonder with a little ventilation if it would sustain this level indefinately...right now it is on the bottom of an old end table with no circulating air...aybe this would be a good experiment for me. Anyway, the unit came back on and had no issues running at sane levels right away.

I think Emo really shows a high level of dedication to their customers. They worked with you extensively and even chimed in here...after reading this whole thread I concur that your needs simply exceed what this amp can do.

Question - what kind of power are we talking here to get the SPLs you are looking for in an 8000 cubic foot room?
Posted by: PeterChenoweth

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/11/07 09:27 AM

Quote:

I'm sorry I even started this thread.




As an Emotiva owner myself, I think this is a great thread. You're having a problem, and we're all working through it. Seeing Dan logged in here is rather interesting. Damage control on the one side, but also nice that he's taking an interest. Right in line with the couple of email/forum discussions I've had with he and Lonnie. Customer service that's on par with Axiom, and that's high praise.

Sirquack, what you ought to do is purchase a different amp of similar rating that has a full money back return policy. Like an Outlaw 7200 or 7500. Obviously this requires some financial outlay (it's so easy to spend other people's money!), but you would certainly return one or the other at the end of the test.

Run it at the same level as the MPS-1 and see if you get any shutdown problems. If you do, well, then we'll all learn that it truly isn't an amp problem, but just the size of the room and the volume you are trying to drive. Simple physics. If you don't have shutdown problems, then we all learn that Outlaw (or whatever) > Emotiva, that not all amps are created equally, and that 200w != 200w. There's no better time to evaluate equipment than when you have a known, reproducable flaw. We can argue until the cows come home about sound quality or watts produced, but direct evidence that one amp can push out more power for longer periods of time than the other, or that both shutdown at about the same volume is pretty cut-and-dry.

The point is, it's now mostly conclusive that there's nothing wrong with your MPS-1, and that the MPS-1 in general doesn't have a problem (according to Emotiva). You are still having shutdown problems. Therefore, the MPS-1 doesn't meet your needs. Hard to believe that such a monster amp system wouldn't be enough for anyone, but there it is. I'm not an electical engineer, so I still find it hard to understand why your Denon AVR doesn't seem to have the same problem.

Maybe just send it back and save your money for the Axiom Uber-amp.
Posted by: speakergrrl

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/11/07 10:15 AM

Quote:

I'm sorry I even started this thread.




Now, see, there may be hope for you yet, giggle.

My eyes glaze over when I see your posts. Are you sure you're not an engineer? Oh yeah, you are an accountant and just as obsessive as the best/worst engineer.

I just like to pop in from time to time to see what kind of feedback you get. Like ENJOY THE MUSIC!

TTFN!
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/11/07 11:27 AM

Hey Whitney

I work in IT as a System Administrator, however, my major was Accounting for my first year in college.

Just to let everyone know, Tharkun, who used to frequent this forum had shutdown problems with Outlaw and Parasound multi channel amps driving 5 m80's also. His room is about my size. It was not until he went to a 2-channel Halo Parasound amp that he has had no problems.

What is sad is that I can run my Denon by itself at higher volume levels with no problems. +3 is really not asking much, and we are talking a 300 watt amp versus 100 watt AVR.
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/11/07 11:41 AM

Another thing I have not mentioned. The mps-1 does not shutdown using my Qs8 6ohm speakers, or another guy at work's m60's 8ohm. He brought them over this last weekend since I don't own my m60's anymore. Just driving the m80's is the issue. oh well
Posted by: Wid

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/11/07 11:47 AM

What kind of spl levels did you reach with the M60? Did you get a chance to A/B the 60s and the 80s?
Posted by: PeterChenoweth

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/11/07 11:53 AM

The problem with all this is that the MPS is supposed to be stable down to 2 ohms. Obviously 4 ohm speakers pull more current than 8 ohm, which will stress the amp. You're saying it's fine with 8, fine with 6, but not fine with 4. What would 2ohm speakers be like? That worries me a bit regarding the specs of the amp, and this is supposed to be their flagship product.

It's pretty clear to me that you probably ought to just send the MPS back and call it a learning experience. If your Denon works, why not just enjoy it? I like to tinker as much as the next guy, but it seems that this situation is causing quite a bit more grief than it should. This hobby is supposed to be fun!

But I'm still curious if bi-amping your M80's would help the situation....

Quote:

Another thing I have not mentioned. The mps-1 does not shutdown using my Qs8 6ohm speakers, or another guy at work's m60's 8ohm. He brought them over this last weekend since I don't own my m60's anymore. Just driving the m80's is the issue. oh well



Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/11/07 12:45 PM

I was able to go beyond the SPL point with the m60's with no problems where the m80's were shutting down. In regards to 2 ohm, I was told by Lonnie when I brought that up that he was suprised this was on the website, and I believe was going to have it removed.

Ted on AV123 is still having a problem with his Ref 1 bookshelfs (4ohm). Emotiva is having Mark Schifter send them some Ref 1's. They are now thinking it is related to the crossovers or something. They asked if Axiom would give them a schematic of the m80 crossover, this was not available per my email to Axiom for obvious reasons.
Posted by: Mojo

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/11/07 12:54 PM

"Stable down to 2 Ohms" does not mean much. It could be stable at 2 Ohms and 1 watt input for example.

Also, as I have pointed out on another post, there is not much difference between the current requirements for the M60 compared to the M80 at a similar SPL because the M80 is 2 dB more efficient.
Posted by: Wid

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/11/07 12:59 PM


I sure wish I were closer to you so that we could compare the Rotel to the Emo. Sounds like a good 2 channel amp might be the ticket.
Posted by: Hutzal

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/11/07 01:00 PM

Randy,

Although you have had no intention of spreading negativity about Emotiva, I have to admit that I am no longer looking at their amps for a future purchase.

And you know what? I am HAPPY that you had your problems, it gives them a chance to fix whatever is wrong to make their product better. But at the moment, their MPS-1 line is not all it is cut out to be (perhaps with certain speaker models and crossovers like you said).

-Hutz
Posted by: tomtuttle

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/11/07 01:21 PM

I was going to pass up this opportunity to keep my mouth shut, but I want to provide one balance point to what Robb said.

I like this thread, too. I learned (and re-learned) a lot.

As a consequence of the superior customer service Emotiva provided Randy, my ownership of M60's and several other factors, I am considering Emotiva products more than ever.

Now, I don't want in any way to discount my friend Randy's experience. I can't imagine how disappointed he must be. At the same time, I'll echo Peter's observation that Randy's SPL needs in his environment seem to be simply beyond what the product is designed to do. As to the Denon seemingly not having the same problem, I'm not sure there is a way - in this instance - to measure the THD, but I'd wager that the Denon keeps running (and distorting) when the Emo shuts down gracefully.

I want to support and encourage Emotiva's participation in public forums. My opinion (as a prospective rather than current client) remains that their products deliver a decent performance/value ratio and that their hands-on approach will continue to yield even more impressive results.
Posted by: PeterChenoweth

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/11/07 01:42 PM

Regardless, I'm still quite pleased with my LPA-1 & M80 combination.

Volume on my AVR maxes out at +12. I've been there once with the LPA. Playing relatively quiet solo piano music in my 3400cu ft room, that was pumping out 105db sustained with peaks at about 110db from my sofa, 11' away from the speakers. The amp was definitely starting to clip, and my head hurt. I backed it back down to normal listening levels within about a minute. That's supid loud. Hearing-damage loud. I don't know why I'd ever want to go that loud. It's not music anymore, just noise.

<bad car analogy>
It's kind of like my car. The speedometer goes to 160mph, and I know that the Euro version will go 150mph+, but here in the US it's governed to 135mph. I suppose I could be mad about it, but it's just unused potential.
</bad car analogy>

However, in Randy's room, more than twice the size of mine, I can see where you might need more serious amp power.
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/11/07 02:05 PM

I'm going to pick up a piezzo tweeter from Radio Shack to run the test Lonnie told me about. This will tell me when my Denon starts to clip.
Posted by: real80sman

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/11/07 02:24 PM

Hutzal, it's quite unfair of you to state that the line is not all its cut up to be. It's now been proven that it WAS producing the advertised power. Once Randy took it one or two notches PAST, it shut down. Sure the Denon went higher, but with the distortion he was experiencing, I'm sure it sounded like fecal matter.

As I stated before, the same thing happens with my two. When pushed, the Luxman stays clean until it shuts down, and the Yamaha doesn't, but sounds like crap while trying to keep up. So what's the point of even trying?

I will agree that it's frustrating. It sounds so clean that you want to push it higher, but then [click], it's off. We've effectively reached the limit of what the amp will do.

As Randy found out with the lower rated receiver, it could go just as loud, but with tons of distortion. But again, he effectively reached the limit of what the amps would do.

So what would you rather have? An amp that shuts down and protects the speakers, or one that can go past it's limits, distorting, and possibly taking out tweeters in the process?
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/11/07 02:25 PM

Bring on the Axiom amp.
Posted by: dllewel

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/11/07 03:14 PM

If the new Axiom amp passes Randy's requirements, then it should be a real selling point.
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/11/07 03:15 PM

Not if you ask my wife.
Posted by: PeterChenoweth

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/11/07 03:16 PM

Quote:

If the new Axiom amp passes Randy's requirements, then it should be a real selling point.




I think Randy ought to be a beta tester for it.
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/11/07 03:37 PM

I would love to be a beta tester.

ps: I'm tossing the idea of checking on the RPA-1 2 channel dual monoblock amp from Emotiva. It would be interesting to see how it would perform.

randy
Posted by: Hutzal

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/11/07 03:43 PM

Quote:

Hutzal, it's quite unfair of you to state that the line is not all its cut up to be. It's now been proven that it WAS producing the advertised power. Once Randy took it one or two notches PAST, it shut down.




Strange that when Audioholics was testing theirs, they were producing up to 120db peaks? Outside? I can't really remember the numbers.

The fact is, the amp is perfect for some speakers, and for others it seems to have a problem.

I am not actively looking at the moment for a separate, as I am eagerly awaiting Axiom's debut.
Posted by: Wid

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/11/07 03:52 PM


At least it has meters so you would know what kind of power you were using
Posted by: real80sman

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/11/07 04:52 PM

Strange that when Audioholics was testing theirs, they were producing up to 120db peaks?
Measuring at 1 meter? Speaker efficiency & ohms? Could have very well been.

The fact is, the amp is perfect for some speakers, and for others it seems to have a problem.
But is it really a problem when you push it past what it was designed to deliver? Don't forget, Randy was really happy for a couple of months before he got SPL crazy at the Taj Mahal there.

Regardless, I agree that I wouldn't be happy either, and would graciously accept their offer to take it back.
Posted by: pmbuko

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/11/07 05:41 PM

Keep in mind that, due to the limitation of the RS meter, we don't have accurate data about how loudly the M80s are actually playing when the amp shuts down. I see absolutely NO reason to return it, whatsoever.
Posted by: MadScientist

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/11/07 05:46 PM

Quote:

I'm going to pick up a piezzo tweeter from Radio Shack to run the test Lonnie told me about. This will tell me when my Denon starts to clip.




Randy, If you want to run a distortion test on the Denon, then you will need run a low frequency sine wave through the system like 60-80hz. Set your Denon so that it is in PLIIx mode so all speakers are playing. Connect the piezo in parellel with one of you main speakers. I would recommend that you run a long speaker wire so that you will be farther away from the actual main speaker and can hear the tweeter better. Bring up the volume until you hear a buzzing in the tweeter. Listen carefully (like have the tweeter near your ear) and as soon as you hear anything from the tweeter, you are hearing the distortion from the amp and note the location of the volume control. This is how loud you can turn it up without distortion going to your speakers. You will probably be able to turn up the volume a lot more, but you will also notice as you turn up the volume the noise in the tweeter will also increase which means more distortion to your speakers.

I just thought that if you are going to give it a shot, I would give you a quick run down of the proper way.

BTW. I am out of the office right now, but will either call or email you later today.
Posted by: Wid

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/11/07 06:26 PM


Is the RPA-1 based on the same design as the MPS 1 and what is the transformer size of the 2 channel unit?
Posted by: MadScientist

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/11/07 06:39 PM

Quote:


Is the RPA-1 based on the same design as the MPS 1 and what is the transformer size of the 2 channel unit?



The RPA-1 is based on the same design as the MPS-1. They are both Dual Tracking Class H amplifiers but the RPA does not have the wave form limiter (hard core stereophiles want all the dynamics they can get) and the transformer is slightly larger (400VA/ per channel vs. 350VA on the MPS-1). This increase in copper will offer greater dynamics but will not sustain a continuous increase in SPL. Also the VI sense on the protect circuit will still kick in if the amp is run into hard clip.
Posted by: Wid

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/11/07 06:43 PM


Thank you for the information. I do like the looks and specs of the 2-channel unit; if I were in the market for an amp I would certainly consider one.
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/11/07 08:37 PM

I went to RS, and the guy had no idea what I was talking about. I searched their website, but not really finding anything called a Piezo Tweeter? I see them on Ebay. Maybe Radio Shack no longer sells them, hmmmm.
Posted by: littleb

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/11/07 10:01 PM

I miss meters, they were
Posted by: dlaufman

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/12/07 12:16 AM

Hi Randy,
Hi apologize for getting some of your comments confused with another MPS-1 owner. It's just that after reading some of these posts on the different forums (not necessarily yours), my head is going to explode from the lack of technically accurate and meaningful discussion in some quarters.

I appreciate the desire to understand and discuss this issue, but the way to deal with and understand this type of problem is to approach it in a scientifically verifiable, repeatable, and valid manner. One must also compare apples to apples.

Please understand that my comments are not directed you or anyone in a personal or disrespectful manner; I just want to set the record straight, from my perspective. I guess my main points were this...

1. The attenuator indicator of the receiver volume control is meaningless for our purposes. The gain structure of the amplifier is probably different than the internal amp in the receiver. So, +X or -X dB doesn't tell us anything of value.

2. The fact that the receiver doesn't not shut down at x dB compared to another amp is again, not meaningful. What is the THD? What is the real power level? Does distortion or dynamic compression matter to the listener? Is it just about being able to crank the knob up all they way; like flooring a car?

3. The MPS-1 has a VI limiter that WILL shut down the amp when it is drive into HARD clipping. It doesn't make the amp bad or weak, just intelligent. I am a HT nut, I play my movies LOUD; I can't be in the same room with my MPS-1 and the speakers playing loud enough to trigger the protect. I also cannot tolerate clipping! In my opinion, this is a VERY bad thing. It ruins your speakers and is very unpleasant. If a person wants to listen to their system in this manner, maybe were not for them; we shut down when this occurs.

4. Our design approach is not a defect or a weakness, it's a decision on our part, like a governor or a rev. limiter on a motor. We think its just good design.

5. I'm not doing damage control, I'm trying to help all of you understand the thinking behind our products and hopefully keep you as a customer. Maybe I'll help you understand the way we approach the design of our products and enlighten others too.

6. Also, I'm hoping to learn from all of you on the forums, and maybe share some of my knowledge with you in the process.

Like you Randy, I don't want to start a controversy. I am very glad you are so into understanding your system and learning about the in's and out of audio gear. I don't want you to feel like you cannot come to us for any type of support or help. We are here to help you and we will try to do our best to keep you and all of our customers satisfied.

I understand that without you and all of our customers behind us, we don't have a business; we know who we work for, and that's all of you.

Thank you all for your support and interest in this great hobby and in Emotiva; we really do appreciate it. Your input and comments are truly appreciated and respected.

Thank you and best regards,
Dan




I
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/12/07 12:38 AM

Dan,

Thanks for posting again, your up pretty late. Wait, so am I.

I will be talking to Lonnie tomorrow to discuss my options. Maybe I can chat with you if your not to busy. One thing that puzzles me is that I'm NOT playing things that loud when it shuts down.

For example, you say you like HT and movies loud. Recently, I had some friends over watching an action/adventure type "guys" movie. The volume on the denon was around -15 which for movies is not very loud. My wife usually watches movies around -20 for "chick" flicks.

Anyway, during one of the parts of the movie, there was some explosion scenes/gunfire/etc... The left amp shut down during one of the explosions? This just does not seem to be normal. I find it hard to believe I'm pushing the amp into HARD clipping at 100dB from 12ft away during music.
Posted by: tomtuttle

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/12/07 11:29 AM

Maybe your cables ran out of electrons. Perhaps if you get them recharged.
Posted by: speakergrrl

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/12/07 11:37 AM

Quote:

Maybe your cables ran out of electrons. Perhaps if you get them recharged.




yeh, like plug them all into the wall, dude, then U will feel mo' better.
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/14/07 04:31 AM

Looks like there is another user on AV123 with Maggies 4ohm speakers that is having the same issue with his mps1 watching movies. So it is not just me and my 80's.
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/14/07 06:09 PM

Out of curiousity more than anything, I tried Bi-Amping my 80's today. Now I know some of you are going to call this "passive bi-amping" or "fools bi-amping" or other names from the past, since I'm not truely using "Active Bi-Amping" and an electronic crossover before the amp and disabling the internal speaker crossovers.

I talked to Alan first and pretty much got the go ahead to give it a try. I wanted to make sure that there would be no issues to hooking up a seperate monoblock to the mids/highs and one to the woofer section. The 80's have a passive hi-level and low-level crossover design.

I will tell you that I did in fact notice a difference, for the better, in the overall bass and mid/high clarity, contrary to belief.

The main reason for this test was I wanted to see if there would be any difference in regards to the amp shutdown issue. I used the same song as in the above tests and specs, and everything else was the same in the setup.

I turned the volume up to the same levels of 100dB average from 12ft away to start, which was at 0 on the Denon main volume dial. I'm just using that as a reference as before.

Anyway, this time I was able to turn up the volume farther than before, however, the amp driving the Bass section did shut down. Before "fools bi-amping" the 80's would shut down on this particular song around +4. With bi-amping, I was able to get up around +8 and then the amp driving the woofer section shut down. Just to let you know, I was able to go further and the mid/highs amp never shut down.

When the woofer section shut down, I was not going over 110dB from 3ft in front of the speaker.

Whatever this tells us....
Posted by: bridgman

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/14/07 06:59 PM

OK, that's going to cause some serious head-scratching.

Without going near the "better sound" part of it, I don't think I even have an explanation for why you were able to turn the volume up higher before the amp shut down.
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/14/07 07:04 PM

John, my guess and I'm sure I'll get slammed for it, is that before I had one monoblock driving all the drivers (6), and now have 2 seperate monoblocks. So one 300 monoblock is probably able to drive the woofers more efficiently/easily by itself, then when it also has to drive the mids/highs also. That being said, I'm guessing it had a little more headroom.
Posted by: dllewel

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/14/07 07:12 PM

Is it possibly because when connected to the woofer only segment of the M80s, the impediance was something higher than 4 Ohms? If it was 6 or 8 then it would require less current from the amp. Interesting... very interesting.
Posted by: bridgman

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/14/07 08:15 PM

>>John, my guess and I'm sure I'll get slammed for it...

Well, bumped maybe, but not slammed. Bumped lots of times... by at least two people named John...

>>... is that before I had one monoblock driving all the drivers (6), and now have 2 seperate monoblocks. So one 300 monoblock is probably able to drive the woofers more efficiently/easily by itself, then when it also has to drive the mids/highs also.

This was discussed a lot recently, not sure if in this thread or another one. Consensus was that the crossover shows a much higher impedence outside the frequency range, so the combined impedence in the woofer range is only a tiny bit lower than the woofer alone. A tiny bit might be enough, I guess...

OK, here's an interesting question for JohnK or others. I think we all agree that you don't get any more *voltage* headroom from biamping without a crossover before the amps (so the amp normally clips at the same input level as before), but I guess you would get a bit less total *current* draw on the woofer side if the impedence outside the woofer frequency range was higher ?

We should look at the M80 impedence curves again to see if the impedence dips in the crossover region between woofer and midrange -- if so, separating the two might eliminate the dip and a potential trouble spot for the amplifier...

>>That being said, I'm guessing it had a little more headroom.

Current, not voltage headroom. Normally that doesn't make any real difference since amps clip when they run out of voltage, but this *is* a hint that the problem might be slightly over-touchy current-sensing circuitry in the amplifier.

It would be fair to say "duh, of course it's in the current sense logic if you only get problems with 4 ohm speakers" at this point but it wasn't so clear to me.
Posted by: PeterChenoweth

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/14/07 10:23 PM

Awesome that the bi-amping helped a bit. Are you running the M80's full range?
Posted by: Wid

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/14/07 10:34 PM

Earlier in the thread you said.

Quote:

Even when I walked up to about 3 ft of either m80, was not even hitting 110dB's, at least what I could see visually with the SPL meter.





This is from today and the bi amping trial. So what exacty changed?



Quote:

When the woofer section shut down, I was not going over 110dB from 3ft in front of the speaker.





Posted by: JohnK

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/14/07 10:47 PM

Well John, the reason that the amp driving the mids/highs didn't shut down is likely the result of two factors: the impedance of the M80s in those frequencies varies from about 4-15 ohms, with an average of about 8-9, so that made things easier; in addition, it's likely that the highest power demand on that particular material occurred in the bass range, so that amp had to handle very little of it.

As to the bass section amp, no, there isn't any difference in the impedance it faced(and current required)before and after; from the published graph it's very close to the nominal 4 ohms, and nothing's been changed, since the bass drivers are of course the same and the crossover circuitry hasn't been changed either.

As to the observed higher setting before shutdown in the bass, there shouldn't be any significant difference if the conditions were identical, since no additional power capacity has been added. The temperature and/or current limiting circuit should shut it off at about the same setting. Possibly there had been longer operation and the temperature was higher when it had shut down at +4 on the previous occasion.
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/14/07 11:22 PM

Thanks Peter, now that you ask that question. In previous tests I had the 80's set to small, with a crossover of 80hz. So the MPS1 amps weren't even getting the entire low freq's.

Today, I actually set the 80's to large, with No Sub turned on. The bass was very nice and tight and full of punch, that is until it shut down.
Posted by: duckman

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/14/07 11:44 PM

This would solve your problem. They used to make a 2ch version that was like 600x2 at 8 ohms.
Posted by: bridgman

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/15/07 12:41 AM

>>In previous tests I had the 80's set to small, with a crossover of 80hz. So the MPS1 amps weren't even getting the entire low freq's. Today, I actually set the 80's to large, with No Sub turned on.

Auggh !!

What happens if you run with the mains set to Small ? Would that be more of an apples-to-apples comparison ?

There's no smiley for this, but imagine me asking the next question through clenched teeth. IS THERE ANY CHANCE THAT THE BETTER SOUND AND TIGHTER BASS MIGHT HAVE SOMETHING TO DO WITH THE DIFFERENT CROSSOVER SETUP AND NOT THE BI-AMPING ?
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/15/07 01:02 AM

This will do the trick. huh Rick


Posted by: Wid

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/15/07 06:56 AM


I bet it would
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/15/07 08:04 AM

I wonder if their warranties are transferable, this one is on Audiogon?
Posted by: Wid

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/15/07 08:23 AM


No they are not.
Posted by: bugbitten

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/15/07 11:22 AM

Quote:

Looks like there is another user on AV123 with Maggies 4ohm speakers that is having the same issue with his mps1 watching movies. So it is not just me and my 80's.




Retraction by Maggie user:

Quote:

My apologies to Dan, Lonnie, Emotiva and all regarding the shut down of my particular MPS-1. After some "extensive" switching around of equipment this afternoon, I believe I have discovered the culprit (in my situation) that is causing the shut down. As I mentioned earlier, I'm using all Maggies in a 7.3 HT. Looking at the Yammy OSD to balance all the outputs rather than the RS meter, for the first time I noticed I had to use unusually more gain to the center channel speaker amp powering the Maggie CC3 than to any of the other speakers. You guessed it. The Maggie CC3 (though less than a year old)is defective and pushed the gain into overload at the amp. Duh! Sorry guys. Funny how we are ready to blame electronics rather than speakers for problems. Hope this has been of some help and, again, my apologies. I'm so glad I discovered this because I truly love the sound and convenience of the MPS-1 and would not want to part with it.




Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/15/07 11:31 AM

Doug have you heard it Emo has received their Ref 1's in to test. Ted (TCS) is another person having similar issues with his 4ohm bookshelfs?
Posted by: bugbitten

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/15/07 11:33 AM

Quote:

Doug have you heard it Emo has received their Ref 1's in to test. Ted (TCS) is another person having similar issues with his 4ohm bookshelfs?




No. I have thought about asking Dan if he would like to use my M80s for a test, but I'll wait for the Ref-1s testing.
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/15/07 11:44 AM

I mentioned that to Lonnie once, but he said you most likely would not want to do that, they would tear the 80's apart to look at the guts. He asked me if I could get schematics of the 80's crossover design, so they could study what the amp is seeing, however, this was not available from Axiom, which I understand.
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/18/07 02:32 PM

Just to let you all know so you can stop worrying, I have returned my Emotiva equipment. I want to thank Emotiva for their technical support and customer service. I'm sure there will come a day where I am once again an Emotiva owner. Their future products, from what I've been told look promising.
Posted by: speakergrrl

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/18/07 03:34 PM

I for one will sleep better tonite!
Posted by: Spoiler

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/18/07 04:33 PM

Well Randy, I think most will agree that it was a good move on your part for now. I don't think what you were asking of your amps was unreasonable, especially when there are those of us with no issues like that. I don't often go to crazy levels, but when you get the urge to, your system should perform!

Good luck in your search for your next amp, I'm sure you'll nail it!
Posted by: Spoiler

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/18/07 04:37 PM

speakergrrl... avatar ... too... distracting....


must...not...approach monitor!!!
Posted by: speakergrrl

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/18/07 04:43 PM

heh, got you boys right where I want you!!!!!

I PMd somebody who will remain anonymous and told him he could lean in and kiss me but he said he didn't think he could handle me. hmmpmh!
Posted by: CV

Re: Emotiva MPS-1 shutting down? Amp gurus help - 04/18/07 07:32 PM

Yeah, I think if you're any type of "grrl," you're automatically beyond handling range.
Posted by: Hutzal

Re: Emotiva MPS-1 shutting down? Amp gurus help - 05/02/07 03:29 PM

Here is a quote from the IPS-1 Review from Audioholics today, no doubt about Randy:

"As with the Emotiva MPS-1, the IPS-1 displays channel status with LEDs which, when operating normally, will illuminate blue or will turn red during fault conditions. Gone, however, was the very thoughtful and costly soft clipping circuitry which was basically inactive in all but the most demanding operating conditions. The reason being is Emotiva fielded numerous calls from MPS-1 users whose listening habits bordered on sheer insanity managing to shut their amplifiers down using moderately efficient highly reactive 4-ohm tower speakers in large listening rooms. Because of this, Emotiva decisively removed the soft clipping circuit so these users could rejoice in the sonic bliss of speaker compression and constant amplifier clipping while they enjoy their compressed MP3 downloaded music from Napster."

Make of that comment what you will. Looks like they forgot to mention that the MPS-1 just was underpowered. This is kind of out of character for Audioholics...perhaps they didn't get the whole story from Emotiva.
Posted by: PeterChenoweth

Re: Emotiva MPS-1 shutting down? Amp gurus help - 05/02/07 03:32 PM

Why do I hear Larry the Cable Guy saying, "Now dat der is funny!"

That is a bit of a rude comment by Audioholics...

Quote:

Here is a quote from the IPS-1 Review from Audioholics today, no doubt about Randy:

"As with the Emotiva MPS-1, the IPS-1 displays channel status with LEDs which, when operating normally, will illuminate blue or will turn red during fault conditions. Gone, however, was the very thoughtful and costly soft clipping circuitry which was basically inactive in all but the most demanding operating conditions. The reason being is Emotiva fielded numerous calls from MPS-1 users whose listening habits bordered on sheer insanity managing to shut their amplifiers down using moderately efficient highly reactive 4-ohm tower speakers in large listening rooms. Because of this, Emotiva decisively removed the soft clipping circuit so these users could rejoice in the sonic bliss of speaker compression and constant amplifier clipping while they enjoy their compressed MP3 downloaded music from Napster."

Make of that comment what you will. Looks like they forgot to mention that the MPS-1 just was underpowered. This is kind of out of character for Audioholics...perhaps they didn't get the whole story from Emotiva.



Posted by: MarkSJohnson

Re: Emotiva MPS-1 shutting down? Amp gurus help - 05/02/07 03:38 PM

Quote:

"while they enjoy their compressed MP3 downloaded music from Napster."



I've always had respect for Audioholics, but that's uncalled for.

It's not simply a matter of defending Randy, it's that Gene crosses over from an equipment review to a snobby editorial with that little addition.....
Posted by: Hutzal

Re: Emotiva MPS-1 shutting down? Amp gurus help - 05/02/07 03:41 PM

ya, I was a bit taken back by that comment.

Right now I am not impressed by either company. It almost sounded like Emotiva was getting defensive about their amps and started to trash their former customer?
Posted by: PeterChenoweth

Re: Emotiva MPS-1 shutting down? Amp gurus help - 05/02/07 03:57 PM

I have mixed emotions about Emotiva.

On the one hand, I really do like my LPA-1. I feel that it does add enough 'audio value' to my system to be worth the $499 cost. I've not had any shutdown problems driving bi-wired (nor regular wired) M80's, and I love the added presence and headroom it added over my AVR.

But on the other hand, I don't really know if they're as much of a 'straight shooter' as they make out to be. My opinion is that I do believe that they are trying to focus on their customers, but a few of the cost-saving measures of their products are slowing bubbling up.

I know first hand that the LMC-1's software is basically at a beta level. These rumors here of the MPS being underpowered (let's be fair, it *could* be something weird about M80's, and not the MPS). The screwed-up DD DSP implementation of the LMC-1. Quiet rumors of similar 'quirks' with the MMC-1. Comments of, "well, they (the LMC/MMC) just have a higher noise floor than you're used to". These discussions are making me a bit nervous of the company, even though I *want* to like their product and be an 'evangelist' for them.

That Audioholics reviewer obviously had a conversation with someone at Emotiva, "yeah, we used to have that great feature but we got so many complaints that we removed it." I find it hard to believe that a company would change a whole product line because of just a few users. And also, if this problem was specific to M80's, we'd hear more about it here. Just sort of an odd situation.

Whether the 'dumb, deaf MP3 blaster' comment is from Emotiva or Audioholics, we'll never really know. That is certainly the kind of comment that's pretty shocking to read in a review where one would hope for a fair and balanced opinion.

I've had some great email correspondence with Lonnie, apparently their senior tech. He seems a great guy. Very insightful and helpful. The posts by the president, Dan Laufman, over on AVS and AV123 also seem to show that they care. But at some point it becomes put-up-or-shut-up.

Quote:

ya, I was a bit taken back by that comment.

Right now I am not impressed by either company. It almost sounded like Emotiva was getting defensive about their amps and started to trash their former customer?



Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 05/02/07 04:05 PM

This is very interesting and a bunch of bull$hit, I guess I'm done looking up to Gene and the guys.

First of all, I don't listen to compressed MP3's, heck, I don't even have an mp3 player, so not sure what left field that comment originated.

It was the owner, DAN, that asked me to borrow an Ipod from someone to hook directly to the amp, to rule out the Denon. He thought the pre-outs of the Denon were clipping and shutting down the MPS-1. The Ipod does not have enough power to use, and Lonnie from Emotiva even said it was a stupid test.

Also, if you read Gene's original review of the MPS-1 he had THE SAME PROBLEM in a LARGE room at LEVELS that were NOT INSANE.

His own words were that the soft clipping limiter was kicking in PREMATURELY, AND, he said that the rating of 300 watts into 4 ohms was inaccurate by his measurements. He was hoping that Emotiva would change their documentation after reading his review.

He reported that his amp was shutting down prematurely, and they sent him a new unit that he was able to play at 120dB for hours and hours at one of his Columbian relative parties with no problems.

Guess what, I'm sure they disabled the clipper so he must have been listening to COMPRESSED CLIPPED DISTORTED music.

What a joke.

This is exactly why I'm dealing with Odyssey Amps right now, Klaus is not full of $hit and WILL admit OR FIX his product if it is not operating as stated.

Until these people do an APPLES to APPLES comparison and run 80's in a 8,000+ cubic room and it shuts down at NOT INSANE levels, something is wrong.

Good lord dudes, if an amp does not have enough capacitance to fill dynamic peaks for a few explosions while watching terminator at comfortable volumes, and then shuts off, something is wrong.

peace out
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 05/02/07 04:10 PM

I also forgot to mention that Gene said their documentation is misleading about the capacitors. Since they are wired in "Series" they are actualy 1/4th the mentioned rating. 12,000uF is a big difference than 48,000uF.
Posted by: PeterChenoweth

Re: Emotiva MPS-1 shutting down? Amp gurus help - 05/02/07 04:11 PM

Quote:

Good lord dudes, if an amp does not have enough capacitance to fill dynamic peaks for a few explosions while watching terminator at comfortable volumes, and then shuts off, something is wrong.





And that is about as simple as it gets. Well said.
Posted by: pmbuko

Re: Emotiva MPS-1 shutting down? Amp gurus help - 05/02/07 09:53 PM

That's a very interesting point, Randy. As we all remember from high school Physics class (with a google refresher, of course!), the total capacitance of a circuit of series-wired capacitors is:

C(total) = 1 / (1/Ca + 1/Cb + 1/Cc + ... + 1/Cn)

or, if all the capacitors are of equal value:

C(total) = C / n
Posted by: JohnK

Re: Emotiva MPS-1 shutting down? Amp gurus help - 05/02/07 11:27 PM

Very good, Peter, and you're certainly to be commended for your modesty in claimimg that you had to google to learn the effective capacitance of capacitors configured in series. Yes, it is an interesting point, and I read both the latest Audioholics test and the earlier one(which I'd never studied)to see what the numbers were. Incidentally, I agree that Gene's gratuitous comment about users who had experienced problems was a bit disappointing. It may be that the Emotiva folks didn't give him all the facts.

Back to the capacitance numbers, as Gene pointed out in his earlier test, claiming the total capacitance per channel without clearly indicating that they were in series(for the valid technical reason of increasing the voltage capability beyond what the individual capacitors could handle)was misleading. It should be noted that Emotiva is far from being the only manufacturer playing the capacitance hype game. There appear to be both abuses by merely referring to the total of the individual caps and by implying(or stating outright)that more capacitance than necessary brings some mysterious benefits. The rule of thumb that can be applied is that 50uF per watt is ample and much more than that simply wastes money and takes up space. From that standpoint the Emotiva capacitance is fine and isn't the cause of their problems. Again of course, the effective capacitance should be stated, rather than the misleading total number which apparently is used to impress the innocent.
Posted by: Mojo

Re: Emotiva MPS-1 shutting down? Amp gurus help - 05/03/07 07:09 AM

Capacitance may indeed be over-hyped depending on the application. In the case of the Emotiva amp, 12,500 uF provides a tremendous amount of dynamic power. If we assume that this capacitor bank charges up to a rail voltage of 50V, in a 10 msec drum transient the bank can discharge 62 Amps into the M80s (12,500 uF*50V/10 msec). That's 15,000 Watts of power into a 4 Ohm M80. Looking at it another way, this is 50 times the steady state rating of the amp (300W into 4 Ohms) or about 17 dB of headroom. According to articles I've read, for uncompressed folk, rock and pop music 10 dB of headroom is considered minimum with up to 25dB not unusual. So if you are in an environment where you have the amp operating close to its 300W steady-state limit, you really want this much capacitance and maybe more. But if you're like me and you listen to music with a few watts max, this much capacitance is really just a waste of money. For Randy, the more capacitance the better .
Posted by: a401classic

Re: Emotiva MPS-1 shutting down? Amp gurus help - 05/03/07 11:23 PM

Quote:

I also forgot to mention that Gene said their documentation is misleading about the capacitors. Since they are wired in "Series" they are actualy 1/4th the mentioned rating. 12,000uF is a big difference than 48,000uF.




According to the Emo website...

"Each power amp module contains its own 350VA Toroidal transformer with high speed rectifiers, 4 x 12,000uF 105°C rated capacitors and a fan cooled heat sink."

There is nothing indicating how they are wired. If they are wired is series, would this imply only 3000 uF (or 100 uF / watt), based on the googled formulas?

I've got an MPS-1 and have dealt with Lonnie recently (very recently, today in fact) about a hissing amp issue which was resolved quickly. I've had the DMC-1 cranked to a max indicated volume of -20dB, with a measured spl of 115-120 dB at 12 feet. The speakers were set to large so the MPS-1 was handling the entire load (only 2 channels here). At that level, my clothes were vibrating and the few hairs that I have left on my head were standing on end, vibrating as well. I can't imagine what -0- or a +XX dB setting would do. Of course I've got just a bit over a third the room volume that Randy does. I have not tried to push the envelope with all 7 channels turned up.
I also find it difficult to believe that a review at this level would include a seemingly isolated incedent, unless it's not so isolated. If someone at Emo was venting, the reviewer should have recognized it and left it out.

Scott
Posted by: Mojo

Re: Emotiva MPS-1 shutting down? Amp gurus help - 05/03/07 11:47 PM

Quote:

There is nothing indicating how they are wired. If they are wired is series, would this imply only 3000 uF (or 100 uF / watt), based on the googled formulas?




If they are wired in series, the total capacitance would be 12,000/4=3,000 uF. So my previous calculations have to undergo some revision.
Posted by: JohnK

Re: Emotiva MPS-1 shutting down? Amp gurus help - 05/04/07 02:04 AM

Well, Gene didn't go into great detail about the wiring that he observed, but the arrangement can be inferred from the numbers he gives. If two 12,000uF caps were wired in series(6,000uF effectively)to the positive power supply rail and two in series to the negative rail, then each rail would have 6,000uF of capacitance and this would be consistent with his point that the capacitance per channel would total 12,000uF, rather than 48,000uF.
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 05/04/07 10:12 AM

Well it looks pretty clear to me in the review that it DOES say they are wired in Series, this is right from the review if you actually read the entire review.

website states 48,000uF of power supply capacitance per channel (4 x 12,000uF) for a grand total of 336,000uF total power supply capacitance, it is a bit misleading since these capacitors are actually wired in series and yield an effective power supply capacitance of 12,000uF or ¼ stated in the literature for each channel for a total of 84,000uF. In order to meet the height profile of the card cage, Emotiva had no choice but to use lower voltage caps in series to achieve a higher capacitance working voltage to meet the maximum rail voltage requirements for achieving the rated power. Though a clever design approach, series connecting capacitors cuts the available storage down by ¼ and also doubles the Effective Series Resistance (ESR) as opposed to parallel connecting. Considering this was perhaps the best way of meeting the design profile, I would say this was a good compromise. However, my only gripe is the overstated literature which I am hopeful the manufacturer will change after reading this review.
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 05/05/07 11:50 PM

Oh yeah, PeterC, I forgot to mention I had the 80's set to small with an 80hz crossover.
Posted by: CV

Re: Emotiva MPS-1 shutting down? Amp gurus help - 05/06/07 12:07 AM

The way this thread has turned is definitely making me think again about buying Emotiva, but on the other hand, I don't know if I'll be able to find any amplification that comes close in my price range. Not that I need that much power, but you know, it's that trying to avoid upgrading in the future thing.
Posted by: a401classic

Re: Emotiva MPS-1 shutting down? Amp gurus help - 05/06/07 08:59 AM

Quote:

Well it looks pretty clear to me in the review that it DOES say they are wired in Series, this is right from the review if you actually read the entire review.

website states 48,000uF of power supply capacitance per channel (4 x 12,000uF) for a grand total of 336,000uF total power supply capacitance, it is a bit misleading since these capacitors are actually wired in series and yield an effective power supply capacitance of 12,000uF or ¼ stated in the literature for each channel for a total of 84,000uF. In order to meet the height profile of the card cage, Emotiva had no choice but to use lower voltage caps in series to achieve a higher capacitance working voltage to meet the maximum rail voltage requirements for achieving the rated power. Though a clever design approach, series connecting capacitors cuts the available storage down by ¼ and also doubles the Effective Series Resistance (ESR) as opposed to parallel connecting. Considering this was perhaps the best way of meeting the design profile, I would say this was a good compromise. However, my only gripe is the overstated literature which I am hopeful the manufacturer will change after reading this review.




Randy, I wasn't trying to pick a fight here. You were the main reason I got my big dogs. Although the emo literature is misleading they do not say what the total cap is nor how its wired, so there are no false claims here. Gene is the one who made the assumption if parallel wired to get the 336k that he did, then assumed that they must be wired in series 'cause 336k is way over cap'd. If you read my entry again you'll see that I was finding fault with the review, as well.

Anyway, I went back and re-read the first several pages of this thread (not all) to see if I could duplicte what you were seeing. The first thing I noticed is that you and another Denon owner with another brand amp needed to go +xx dB to get to 75 dB on the test tones. I've got a DMC-1 feeding the MPS-1 and at 13' I get 79 dB at 00 dB for the mains, center, sub and rt surr, -3.0 dB for both back surr (6' away) and +3.5dB for the lt surr (15.5' away)to hit 79dB. Since I was at a neutral setting for the majority of my speakers, I left it at 79dB rather than reduce them just to hit 75dB.
With that said, could the real problem be the Denon?

Scott
Posted by: Wid

Re: Emotiva MPS-1 shutting down? Amp gurus help - 05/06/07 09:06 AM

If he wouldn't have been playing his severely compressed mp3 files at ear bleeding levels then most likely he wouldn't have had any problems .
Posted by: SirQuack

Re: Emotiva MPS-1 shutting down? Amp gurus help - 05/06/07 10:20 AM

I was not trying to pick a fight either, and I'm not sure why I'm still contributing to this thread. I've sent the MPS-1 back and have a new Odyssey amp on the way.

However, the website does state a rating of 4 x 12,000uF per channel or 48,000uF as Gene mentions. This is why he says it is misleading to the reader as each module is actually 1/4th that rating.

Gene is not assuming they are wired in series, as anyone familiar with electronic circuity can just take a look at the amp modules and clearly see they are wired in series. He is a very smart guy when it comes to this stuff.

Anyway, hope you enjoy your mps-1.