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#162644 - 05/03/07 07:09 AM Re: Emotiva MPS-1 shutting down? Amp gurus help [Re: JohnK]
Mojo Offline
connoisseur

Registered: 01/21/07
Posts: 3292
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 .

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#162645 - 05/03/07 11:23 PM Re: Emotiva MPS-1 shutting down? Amp gurus help [Re: SirQuack]
a401classic Offline
connoisseur

Registered: 11/29/06
Posts: 1194
Loc: Alpharetta, GA
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
_________________________
Scott

My HT

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#162646 - 05/03/07 11:47 PM Re: Emotiva MPS-1 shutting down? Amp gurus help [Re: a401classic]
Mojo Offline
connoisseur

Registered: 01/21/07
Posts: 3292
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.

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#162647 - 05/04/07 02:04 AM Re: Emotiva MPS-1 shutting down? Amp gurus help [Re: a401classic]
JohnK Offline
shareholder in the making

Registered: 05/11/02
Posts: 10411
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.
_________________________
-----------------------------------

Enjoy the music, not the equipment.



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#162648 - 05/04/07 10:12 AM Re: Emotiva MPS-1 shutting down? Amp gurus help [Re: a401classic]
SirQuack Offline
shareholder in the making

Registered: 01/29/04
Posts: 13344
Loc: Iowa
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.
_________________________
M80s-VP180-QS8s-EP600-2xEP350 Denon3808 Outlaw7700
M22-OWM22-VP100-Denon2805
Audio Nirvana

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#162649 - 05/05/07 11:50 PM Re: Emotiva MPS-1 shutting down? Amp gurus help [Re: PeterChenoweth]
SirQuack Offline
shareholder in the making

Registered: 01/29/04
Posts: 13344
Loc: Iowa
Oh yeah, PeterC, I forgot to mention I had the 80's set to small with an 80hz crossover.
_________________________
M80s-VP180-QS8s-EP600-2xEP350 Denon3808 Outlaw7700
M22-OWM22-VP100-Denon2805
Audio Nirvana

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#162650 - 05/06/07 12:07 AM Re: Emotiva MPS-1 shutting down? Amp gurus help [Re: SirQuack]
CV Offline
Founder, Axiom Upgrade Club
shareholder in the making

Registered: 07/20/06
Posts: 11269
Loc: Richland, WA, USA
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.

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#162651 - 05/06/07 08:59 AM Re: Emotiva MPS-1 shutting down? Amp gurus help [Re: SirQuack]
a401classic Offline
connoisseur

Registered: 11/29/06
Posts: 1194
Loc: Alpharetta, GA
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
_________________________
Scott

My HT

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#162652 - 05/06/07 09:06 AM Re: Emotiva MPS-1 shutting down? Amp gurus help [Re: a401classic]
Wid Offline
axiomite

Registered: 06/22/03
Posts: 6722
Loc: The Peoples Republic of Il.
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 .
_________________________
Rick


"A fear of weapons is a sign of retarded sexual and emotional maturity." Sigmund Freud


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#162653 - 05/06/07 10:20 AM Re: Emotiva MPS-1 shutting down? Amp gurus help [Re: a401classic]
SirQuack Offline
shareholder in the making

Registered: 01/29/04
Posts: 13344
Loc: Iowa
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.
_________________________
M80s-VP180-QS8s-EP600-2xEP350 Denon3808 Outlaw7700
M22-OWM22-VP100-Denon2805
Audio Nirvana

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