Axiom Home Page Forums General Discussion Technical Questions Amplifiers for the LFR speakers

Wanted to get some opinions on amps for the new LFR speakers. I asked about the amplification requirements a few weeks ago and when I got the info on here I thought I might go with the Outlaw 2200s. When you buy more than one you can get better pricing. Thought about getting 5. 4 for the LFRs and one for my 180.

Someone recommended the Onkyo PA-MC5500 but after reading up on it the specs read 150 watts per channel with 2 channels driven. And I understand the LFRs require equal amplification so if I understand this correctly this amp would not work.
So I am also considering the Emotiva XPA-5 at 200w x 5 all channels driven at 8 ohms and 300w at 4 ohms.

And last the Emotiva UPA-1 monoblock. 200w 8 ohms, 350 4 ohms.
The XPA-5 would be the least expensive at 899.00 and right now 10% off followed by the Outlaws at 1324.00 for the 5 of them and then the UPA-1 at 1745.00 for 5 with an additional 10% off.
So what are some opinions on these or if someone has better suggestions please feel free to post your advice.

Value the experience and advice available here.
Thanks

Sbrown is going to be using the outlaw monoblocks.

Axiom is coming out with an amp specifically for the LFR's as well...

I would get the XPA-5 out of the list you have presented. if you get 5 UPA-1's you will have 1,500VA worth of power supplies, if you go with a XPA-5 you will have 1,200VA worth of power supply, for less than 1/2 the price. Personally, when i am buying an amp the power supply is one of the largest factors that goes into my purchase, next is the power rating when the impedance halves.

Outlaw does not list their power supply ratings, at least not what i could find anyhow..

Thanks for the advice. I think for the money the XPA-5 sounds good, but wanted some advice from some of the guys on here that know a lot more of the technical stuff than I do.

http://www.axiomaudio.com/boards/ubbthreads.php?ubb=showflat&Number=311937&page=1

Here is a technical thread on amps in general, if you read this you will see why i made the recommendation that i did for you.

Thanks for the link. Read a little of it and so far quite interesting.

I love my Outlaws. Was not to fond of Emo's when I tried them years ago.

My Onkyo amp was clipping and would shut down with the M80's and the Outlaw mono's don't even break a sweat at high volumes. Like I said before, my cable box runs hotter than these little guys.

I am quite impressed with them, the only thing is there are so many plugs but I got that figured out now so I am very pleased with my choice.

After doing some more thinking, i would wait on getting an XPA-5, until we know if that amp can handle the LFR front driver array.. Other users have had problems with the emo amps and M80's.. The LFR's will want more power than M80's... If you do buy an Emo amp, i would buy at the same time the LFR's are delivered, incase the Emo's can not handle the LFR's.. You don't want to be out of your return window if the XPA-5 can not handle the LRF's without shutting down...

Outlawn amps seem to be more robust than the Emo amp's. Per your options the XPA-5 offered the best "value"..


What is your budget? Also, do you mind buying pre-owned? if you are open to pre-owned amps that opens a whole lot more options for the $$... however, if you are not interested in pre-owned i can understand that...


If you go pre-owned i would recommend buying this amp fast. I bought the same model, and paid 1700$ 2 or 3 years ago, in the depths of the recession. The one i bought had been serviced recently though....
http://www.ebay.com/itm/KRELL-KAV-250-Po...d#ht_512wt_1348


I was thinking about getting one of these to power the rear speakers of the LFR's, a kav150a.. But decided to go another route.
http://www.ebay.com/itm/330720318711?ssP...9#ht_500wt_1182

If you were to buy the 2 amps above, you would be right at 2k$ the kav150a's have been going for between 800-1,000$ recently, with these two amps you would have WAY more power than the other options that you have presented. But, these would be used amps... With that being said, they are used amps from the 90's from one of the best amp manufactures around, so they will last forever and i would consider them to be a good investment...

To small of a power supply for all of the channels that the amp has, and not a robust design of the amp channels to handle high current... This is why i did not recommend the Onkyo initially... It would be fine with 6+ohm speakers, but not 4ohm or sub 4ohm speakers at higher volumes... the amp channels can not handle the current that the M80's and LFR's will want.

When you get to speakers that have 4ohm and sub 4ohm impedance graphs, then driving them becomes substantially harder for an amp. Andrew has said that the absolute minimum impedance that the LFR's will see is 3ohms, and most likely 3.5ohms... When buying an amp for low impedance speakers, an important factors is the minimum impedance, not the nominal.. If you buy an amp that can barley handle the nominal impedance, when you actually use the speaker, and the impedance dips below the nominal rating... Well, thats when amps start over heating, clipping, and eventually shutting down on thermal protection ect....

Mono amps would be the ideal solution, because each amp channel would have it's own independent power supply. The benefits of which i believe were discussed in the previous thread that i linked you to.

Good luck with your decision.. Have you placed your order for your LRF's yet?

That's a good point Alex, the mono's have more energy(on demand) because of the separate power supplies. My M80's are finally happy, LFR's... hope you like my family!

Ok, I have been running these two mono's for over two hours playing around 69 or 70. Reference is too loud for my room which is 82 and NO heat, nothing. Room temperature?

I will really be liking these units in the summer,whoohoo!

Thanks for all the info guys. We had a grandaughter that was born on Wed and our daughter called right after my last post this morning and had to rush to the hospital. The new baby has some posible heart problems so we have been there all day. But looks like it is not going to be as serious as we first thought. So makes this audio stuff not quite as important.
Anyway, yes I have already ordered the LFRs. Not opposed to used stuff, but I have been burnt on Ebay in the past. Not saying I would not go that route. The first ones you mentioned have now gone on the bidding instead of the buy it now so will see how it goes.
Looks now like the Outlaws may be the best option after the response from Sbrown.
I have read some reviews and thought that maybe the Emotiva problem may have been fixed, but if I went that route would take the advice and wait until time for the speakers to order that.
Thanks again for the replies. Will let you know what I decide.

Best wishes for your grandaughter, Steve.

Steve, best luck to you and yours. Glad to hear that it's not as serious as you first thought. Hang in there.

Thanks for the well wishes. It is our youngest daughters first. The hardest part was seeing our baby so upset. But like I said, looks like it will be ok. We know more tomorrow once all the tests are back.
Thanks again.

dakkon, the second amp you mentioned on Ebay was sold at 5 this afternoon. Was not home in time. I will keep an eye on the other one and see how the bidding goes. Would like to stay under 2000.00 total for the amps.

Hope the tests come out well...


I agree, having spent 6 years in the military you learn about priorities..


Let's make sure you get the correct amps for your budget that will give you the maximum performance.



I have gotten burnt on ebay before as well. However, all of my used audio transactions have gone quite smoothly.


Darn, that's to bad, the seller had a buy it now for 1,000$....


Honestly i am not sure if Emotiva has gotten their problems fixed or not...



Just wait until Mark finds this thread, he is going to be sooo jealous.... It's gona be GREAT...

P.S. Steve, how many total channels of amplification do you need? do you have a 5 channel setup, or is this going to be strictly a 2 channel system?

Hey dakkon, I retired from the army. 28 years.
I have a 7.1 setup. Using an Onkyo 3007. I will use it with my amps. I really only need amps for the LFRs. I was just thinking about using an additional amp for my 180 if I went with the monoblocks. Then use the Onkyo for the surrounds. But all I have to have is the 4 channels for the LFRs.

Steve, your understanding is incorrect in part. As Andrew pointed out about a month ago, there is no "equal amplification" requirement. The max power ratings(if different amplifiers are being used for the back drivers and the fronts)can vary widely, as long as both are sufficient for the required sound levels. Andrew suggested that the amplification for the back drivers would be sufficient if it was about 60% of that available for the fronts. The important factor was that the gain(a fixed factor)was equal for the fronts and backs so the intended front/back balance could be maintained. This would be the case if a HT receiver or separate amplifier with identical channels(and say a 100 watt or more maximum output capacity)was used. If a setup with different amplifiers with different gains was used, some level control to correct for the different gains would have to be used.

John, i e-mailed Andrew about this.. At the time there were 3 different amps that i was looking at, the variation in the gains were 0.6DBW from the amp that i already had. Andrew said that .6DBW would an acceptable deviation, but identical gains would be ideal.


The amps that i will be using have different power ratings.. The amp for the fronts is rated for 600W @4ohm, and the rear channels will be powered by am amp with a rating of 500W@4ohm.

Where have you been John? it seemed like you disappeared......

Must've been a good massage!

Alex, I was only entirely away yesterday. The DSL modem had been operating intermittently for a couple days and was down completely yesterday. After having it tested, I bought and installed a new one today.