who used prosound amps in their home theater?

[sphynx_000]

I am just curious how it works out for everyone?

The price/watt makes them really tempting, but I just think it would be a hassle always having to turn them on and off?

Also what about fan noise? Anyone have an amp with a really quiet fan that wont interfere with movies?

[---k---]

I use a Behringer A500 for my mains. Not a pro, but... It is similar in price/performance to much of what you're thinking about. Good price, very solid amp. I just leave it on all the time and don't look at the electric bill. It doesn't have a fan.

I use a Behringer pro amp for my sub. I get my butt off the chair and turn it on for movies and semi-serious music listening (I never do _serious_ listening). But most of the time if I'm surfing the web or reading with tunes on, the sub stays off and I live with the bass being rolled off at the crossover and non-existent. Which is a nice thing about having large mains now.

Also talked about a lot here a while ago was the Emotive $499 amp. Not a pro amp, but best bang for the buck. A few here really love theirs. If I were expanding amps for every channel, I would be torn between 3 A500's and the Emotive amp.

If you want to go with all pro amps, you can always get a power conditioner that has a sequencer and DC triggers in it.

[dynamowhum]

Currently own Behringer 2500 and 1500. Like them a lot. Ordering to more 1500 Sept 25th.

[sphynx_000]

I am also considering an A500 for my sub. The non fan design is appealing to me.

europower's are al little out of my price range at the moment.

[---k---]

A500 is not a good choice for a sub.

[ThomasW]

If you watch some of the bigger the prosound sites like Zzounds, Musicans Friends, etc, frequently you'll find either refurb EP amps or new Nady XA amps for $150 a pop. These are of course all fan cooled.

For example..

http://www.musiciansfriend.com/product/Nady-XA900-Pro-Stereo-Power-Amp?sku=482052

These are short term specials and the offers usually only run a couple of days

[geoffstgermaine]

I run a Crown XTI-2000 for my subwoofer. I am planning to run all pro amps for my dedicated HT once I get it up and running.

[littlesaint]

Currently own Behringer 2500 and 1500. Like them a lot. Ordering to more 1500 Sept 25th.

I believe the 1500 is a class AB design while the 2500 is class H. YMMV, but in theory the 1500 would be better suited to loudspeakers than the 2500. My reasoning being that class H amps tend to have issues with higher frequencies compared to AB amps. The 2500 would be good for a subwoofer though.

[JonW]

You might want to look over on the DIY forum at avs. Chuck ( chasw98 ) has been doing some testing of those pro amps. I haven't read the thread, but I spoke with Chuck. I think he mentioned that some of those pro amps actually roll off before 20,000 Hz. So they're fine for a sub or a large concert. But maybe not great for a critical music system. Look at Chuck's data (if he posted that) to see if that's the case.

[sphynx_000]

The nady amps are in my price range.

The XA-700 does 750 watts at 8 ohms (bridged), which is perfect for me.
The XA-900 does 900 watts at 4 ohms (bridged), based on that 8 ohms bridged would be around 450 watts.

Is it possible that the XA-700's 750 watts is max power? If not that is the amp I will get.

[nayr]

I use a Behringer A500 with my Nat P's, and they sound fantastic together.

[engr_dave]

Using a Crown K2 on my front subs. Good power (1250 w/channel @ 2ohms), runs cool with no fans, small size, nice protection features, great sound. Would probably make a nice mains amp. Highly recommended.

[ThomasW]

Using a Crown K2 on my front subs. Good power (1250 w/channel @ 2ohms), runs cool with no fans, small size, nice protection features, great sound. Would probably make a nice mains amp.

Our very own JonMarsh was directly involved in the development of the Crown K Series. He recommends running them no higher than ~370Hz.

[Dennis H]

I believe the 1500 is a class AB design while the 2500 is class H. YMMV, but in theory the 1500 would be better suited to loudspeakers than the 2500. My reasoning being that class H amps tend to have issues with higher frequencies compared to AB amps. The 2500 would be good for a subwoofer though.

I can't think of any reason that should be true. Class H, as done by QSC and Behringer, just means the power supply voltage is variable and can be reduced to save energy and reduce heat if the full voltage isn't needed, i.e. you aren't powering a rock concert. The input and output stages are still good old Class A/B and should sound nearly identical to the Class A/B units within the same model range.

[littlesaint]

I can't think of any reason that should be true. Class H, as done by QSC and Behringer, just means the power supply voltage is variable and can be reduced to save energy and reduce heat if the full voltage isn't needed, i.e. you aren't powering a rock concert. The input and output stages are still good old Class A/B and should sound nearly identical to the Class A/B units within the same model range.

If that's case, you'd be correct, but they list it as Class H linear output, and the schematics would also indicate it is class G/H depending on your definition of those. Class G/H amps are known for having issues in the upper frequencies, and are not regarded as HiFi amps like their A/B cousins.

[Dennis H]

If that's case, you'd be correct, but they list it as Class H linear output, and the schematics would also indicate it is class G/H depending on your definition of those. Class G/H amps are known for having issues in the upper frequencies, and are not regarded as HiFi amps like their A/B cousins.

Please explain. I agree that QSC seems to use a bit different definition from some and many would call it a class G. But why the "issues in the upper frequencies" other than "known" and "not regarded"? It's a serious question, I've never heard those claims and can't think of a theoretical reason why they need to be true. Of course you can always find poorly done examples of any amp class but the QSCs are generally well regarded.

[littlesaint]

Please explain. I agree that QSC seems to use a bit different definition from some and many would call it a class G. But why the "issues in the upper frequencies" other than "known" and "not regarded"? It's a serious question, I've never heard those claims and can't think of a theoretical reason why they need to be true. Of course you can always find poorly done examples of any amp class but the QSCs are generally well regarded.

In theory, the "switching" in these amps can introduce noise and distortion most noticeably in the upper frequencies. I may be splitting hairs and no doubt this makes no difference in sub amps or perhaps even HT, but for critical 2Ch listening, I would prefer class A or A/B. Now, I'll concede that a well designed class H amp ($$$) should not have these issues, and I will say the only one I've actually owned (Sunfire) was pretty good, but it is 4x the cost of a QSC let alone Behringer.

BTW, the Behringer EP2500 is almost a direct copy of the QSC RMX2450 design.

EDIT: Here's a thread with lots of info.....and opinions

http://www.diyaudio.com/forums/showthread.php?threadid=68415

[royceb]

I use the Crown XLS400 amp. The fans are loud, but a simple mod by replacing the fans with quieter fans did the trick. The new fans are not audible when watching movies or listening to music.

[whoaru99]

In theory, the "switching" in these amps can introduce noise and distortion most noticeably in the upper frequencies. I may be splitting hairs and no doubt this makes no difference in sub amps or perhaps even HT, but for critical 2Ch listening, I would prefer class A or A/B. Now, I'll concede that a well designed class H amp ($$$) should not have these issues, and I will say the only one I've actually owned (Sunfire) was pretty good, but it is 4x the cost of a QSC let alone Behringer.

BTW, the Behringer EP2500 is almost a direct copy of the QSC RMX2450 design.

EDIT: Here's a thread with lots of info.....and opinions

http://www.diyaudio.com/forums/showt...threadid=68415

For critical listening, you're probably not anywhere close to where one of the QSC amps would change rail voltage. So, in effect, for all but very high levels, they're quite likely functioning as pure Class A/B - if it even matters.

The Carvers are more of a fully tracking power supply, AFAIK, with rail voltage constantly changing to remain just a bit over any given requirement.

[sphynx_000]

I am going to order a nady xa-700 and hope for the best. The first thing I am going to do is replace the fans and possibly put a switch so I can turn them off during movies (when the amp shouldn't be driven that hard).

Does anybody know the fan size?, and have some recommendations for a quiet replacement?

[---k---]

$129 is a great price on the Nady, but by the time you screw with ordering 2 - $12 fans and paying $10 shipping, are you really gaining much on the $199 Behringer A500? Basically the same power, but the A500 is fanless, has rca connections, and is made for home use. And if you don't like it, it will be much easier to sell then a warrenty voided, modified Nady.

Just my opinion. I'm getting old and saving a few bucks isn't worth it to me any more.

EDIT: For some reason, I keep thinking that this is to power mains speakers. I don't know. If it is for a sub, do NOT get the A500. If it is for a sub, follow Thomas's advice below. If it is for the mains, get the A500.

[ThomasW]

Is it possible that the XA-700's 750 watts is max power? If not that is the amp I will get.

It's the max power listed when the amp is run in bridged mode.

With subs it's all about having power to spare, so IMO the extra $30 for the XA-900 is a good long term investment.

[zzzz]

$129 is a great price on the Nady, but by the time you screw with ordering 2 - $12 fans and paying $10 shipping, are you really gaining much on the $199 Behringer A500? Basically the same power, but the A500 is fanless, has rca connections, and is made for home use. And if you don't like it, it will be much easier to sell then a warrenty voided, modified Nady.

Just my opinion. I'm getting old and saving a few bucks isn't worth it to me any more.

I second Thomas' opinion. $pend a bit more!

When I discovered just how annoying the noise from the NADY 900 W amp was I returned it the next day. Replaced it with an oaudio 500 W sub amp - only an extra $60 cost. A great decision in hindsight!

[---k---]

See my edit above

[sphynx_000]

This amp will be used for subs if anyone didnt catch that.


---k---,
you said earlier that the A500 would not be a good choice for subs?,




edit: I just saw k's edit, nevermind.

I am going to try the nady I think. With the money I have to work with, this will be my best choice.

[chasw98]

Please explain. I agree that QSC seems to use a bit different definition from some and many would call it a class G. But why the "issues in the upper frequencies" other than "known" and "not regarded"? It's a serious question, I've never heard those claims and can't think of a theoretical reason why they need to be true. Of course you can always find poorly done examples of any amp class but the QSCs are generally well regarded.

Here is what I measured on an EP1500 at 4 ohms and on an EP2500 at 4 ohms.





Notice the frequency response and the distortion at upper frequencies.

Chuck

[---k---]

sphynx, since this is a sub, you'll be fine with the Nady and a fan mod.

Chuck,
we're getting off topic (but more interesting), first do you think the difference in distortion between the EP1500 and EP2500 was significant? - Yeah it almost 43% increase, but from 0.14 to 0.2 isn't really much overall. If so, do you think the distortion you saw at the higher frequencies is due the different power supplies or something else, such as build quality tolerances, testing tolerances, or whatever?

[kgveteran]

I use (2) A500's for the four surround speakers and (4) qsc 1450's bridged mono.

I use three Outlaw Audio M-200's on the mains (non-pro amps) (I couldn't pass up the deal)

KG

[Dennis H]

Thanks, Chuck. To my eye, there's not a heckuva lot of difference in the behavior of the Class A/B 1500 and the Class H 2500. Neither one does as well at 20K as it does at 1K. And I suspect the distortion figures for the 2500 would be a bit better if you ran it at the same power as the 1500 so I don't see the 1500 as having any real advantage over the 2500 for fullrange use. Do you see it differently?

[chasw98]

sphynx, since this is a sub, you'll be fine with the Nady and a fan mod.

Chuck,
we're getting off topic (but more interesting), first do you think the difference in distortion between the EP1500 and EP2500 was significant? - Yeah it almost 43% increase, but from 0.14 to 0.2 isn't really much overall. If so, do you think the distortion you saw at the higher frequencies is due the different power supplies or something else, such as build quality tolerances, testing tolerances, or whatever?

Ryan:
A standard (sort of) in the prosound industry is to rate an amp at x watts at 1 KHz at .1% THD into x ohms (usually 4). Pro guys really don't count the difference in THD and are more concerned with the amp working than with the "fidelity" of the amp. No, the difference in THD is not significant, audible?, don't know. The higher THD at higher frequencies is Uli Behringers dream of meeting the specs printed on the box. If these amps were tested using pulse burst testing to get a quick snapshot of power & distortion, they would meet specs. But for the good old brute force, hook em up to a load and let them run, they will not meet specs.

Thanks, Chuck. To my eye, there's not a heckuva lot of difference in the behavior of the Class A/B 1500 and the Class H 2500. Neither one does as well at 20K as it does at 1K. And I suspect the distortion figures for the 2500 would be a bit better if you ran it at the same power as the 1500 so I don't see the 1500 as having any real advantage over the 2500 for fullrange use. Do you see it differently?

I have to agree with you 85%. I say that because the 2500 will have some reserve in it due to more output transistors and the capability of handling peaks better.

I will have to say that I quit using my EP1500's and my EP2500's for main and surround duty almost 2 years ago. I replaced them with Earthquake Cinenova amplifiers. There was an immediate and perceptible difference (mostly in the high frequencies) of lower noise and lower distortion in the Earthquake amps vs. the Behringers. A lot of people will say that amplifiers that "say" they perform equally will sound the same. I don't believe it. When you see Thomas or Jon talk about hanging an Ayre or an Aragon amp off of these DIY speakers they build, there is a reason. They sound better! Not because of any flowery talk about open, airy, I smell wildflowers in the spring stuff. Better amps usually can and do sound better. And price is not the deciding factor sometimes.

Chuck

[Lindahl]

I run 4 Crown XLS402Ds for speakers and a Crown XTi 4000 for my subwoofers. Great clean sound, and I love the flexibility of the XTi 4000.

[Dennis H]

I will have to say that I quit using my EP1500's and my EP2500's for main and surround duty almost 2 years ago. I replaced them with Earthquake Cinenova amplifiers. There was an immediate and perceptible difference.....

No kidding! I wasn't trying to say the Behringers are the best you can get, just asking about the A/B vs. G/H thing. Did you ever test a Behringer A500? I just tried finding your thread over at AVS but the server is overloaded.

[chasw98]

I understand Dennis. Here is the link to my amp thread at the other place. I have not gotten a chance to look at an A500. I should have a K2 within a week or 2, though.

Measuring Amplifiers

[AJINFLA]

I've used a QSC 3500 Series 3 for years in my audio system. Certainly could be used for HT. They are often available at used Pro audio online stores and ebay, sometimes less than $300. Fanless, rugged, reliable and powerful. As far as sonics...well, I've never "heard it". Just the recordings as interpreted by my speakers/room. I think.

cheers,

AJ

[oxcartdriver]

Using a Crown K2 on my front subs. Good power (1250 w/channel @ 2ohms), runs cool with no fans, small size, nice protection features, great sound. Would probably make a nice mains amp. Highly recommended.

I use the Crown K2 for a sub amp as well. I have experimented with the K2 for full range. Full range the K2 was OK. I don't have the best set of ears, but I could hear a difference compared to my other amps and prefer my other amps full range. I've had others check and they couldn't tell any difference between the crown and other amps, YMMV.

[joetama]

I have a QSC Series III 3500 I am going to be running on my new HT SUB...

Should be might sexy...

[JonW]

Our very own JonMarsh was directly involved in the development of the Crown K Series. He recommends running them no higher than ~370Hz.

I should have a K2 within a week or 2, though.

I've got a K1 with one channel running my sub and the other running my center channel. Sounds like it's not a good way to run the center channel. I'll look forward to Chuck's K2 tests. :T

[sphynx_000]

I have been reading in chasw98's thread on avs, and think the ep's look like really good amps. Defiantly capable for a subwoofer.

The nady amps would be ok for me, but even with the 900, I would only see 300 watts "max" power to each woofer. Spending a few more dollars to get a behringer that pushes at least 600 "real" watts per channel seems like a much better investment.



BTW, i am also looking forward to results on an A500...

[dlneubec]

I have been reading in chasw98's thread on avs, and think the ep's look like really good amps. Defiantly capable for a subwoofer.

The nady amps would be ok for me, but even with the 900, I would only see 300 watts "max" power to each woofer. Spending a few more dollars to get a behringer that pushes at least 600 "real" watts per channel seems like a much better investment.



BTW, i am also looking forward to results on an A500...

Here is a review of the A500 by the Audio Critic (Peter Aczel)

The Audio Critic

[GMorris]

Another endorsement of the QSC Series Three.

Apparently, this design came about in the early '80s when QSC "...decided to make a statement and create a very high-end amplifier that would appeal to the concert sound market."

More from the QSC history page: "It represented a significant technical advance for the company, combining such innovative features as convection cooling, step-linear output circuitry and removable channel modules into a low-profile package."

http://www.qscaudio.com/corporate/history_page2.htm

Probably best to try to find one manufactured in the later '80s. I've peaked inside two of these amps... The later model has higher-grade Nichicon power caps vs. no-name caps in the early '80s model.

Greg