Using commercial power amps with SDA SRS ?

cobramatteo

I was wondering if anybody has experience powering any of the larger SRS series speakers using say a Crown XLS2500 Power Amplifier.

Spec wise it seems like it would be a great amp, and I have read many reviews of this series of crown amps where folks are using them in home audio setups with success.

Seems like it might be a great solution to those needing big power on a low budget. Only question would be if its a common ground design. I hear these amps are stable down to 2ohms and sound way better than they have a right to.

Also, are the XLR inputs the same as home audio balanced inputs ?

TIA !:biggrin:

westmassguy

I can't speak to the Crown, but can tell you my Carver PM-600 powers my 2As with ease, and it's specs are similar to Carvers Consumer TFM amps . For the Crown, you could easily contact Crown/Harman support, and find out if it's a common ground. On Pro Gear, XLR connectors are Balanced, 1/4" are Unbalanced. Consumer audio uses RCA connectors which are also Unbalanced.

davdcridely

really love road biking and..

zingo

I do not recommend pro amps. They usually have fans (noise), as well a higher levels of electrical noise, and the extra power is not worth the sound quality trade offs. There are many good amplifiers that are higher power if that is your interest, and I recommend a good class D home amp for the money over a pro amp.

cobramatteo

Ok, So I guess the next thing to ask is :

Is there an amp that can be had for less than 2K new or used that can provide close to 800 watts RMS at 8ohms - ?

What is the ideal amp for driving SRS SDA ? - Would two Adcom GFA 555s ran biamped per set of speakers be sufficient, that would be 400 watts RMS going to each speaker.

I have plenty of Adcom GFA 555 and Adcom GFA 5500 amps, also have 3 ea Nakamichi PA amps [ the PA7s can not be bridged ] but being of the STASIS design should offer a little more thump than the Adcoms.

I am overseas in Afghanistan for the next 6 months, but have all this equipment in my house I just bought - trying to get the ideal power solution and would love to meet the 1000 watt per channel rating of these speakers.

F1nut

Pro amps are built for power, not high fidelity.

A 100wpc tube amp will drive them just fine and sound better doing it.

zingo

The Wyred4Sound ST1000 provides 570w in 8Ω per channel and 1,140w in 4Ω per channel for $2000. The Class D Audio SDS-470C provides 300w in 8Ω per channel and 600w in 4Ω per channel for $700. Both also offer a 4 channel version of those amps that would be great for biamping if you wanted to go that route. I like both of those class D technologies and think they sound similarly good with Polk speakers. Either would work great for your 4ohm impedance SDS SRS speakers and much better than a pro amp.

newrival

F1nut wrote: »

Pro amps are built for power, not high fidelity.

Not true. Perhaps with cheap pro amps, but not so across the board. Fan noise can be an issue, but there are modifications for that. Or there are "audiophile variety pro amps out there if one finds it necessary. I will say that the modern non-budget pro amps that I have seen have very low electrical noise. In fact on 101db sensitive speakers, within 3' they were dead silent.

Pro amps do often have a common characteristic of being highly detailed, and neutral to the nth degree, which cam come off as cool or even lifeless if the rest of the system is not taken into consideration. However, for home theater use, and with speakers that could benefit from some clarity, like your classic Polks, I think you would do just fine with those Crown XLS series amps. Dynamics is what you are after. Watts aren't everything, but headroom in a theater is invaluable.

heiney9

cobramatteo wrote: »

Ok, So I guess the next thing to ask is :

Is there an amp that can be had for less than 2K new or used that can provide close to 800 watts RMS at 8ohms - ?

What is the ideal amp for driving SRS SDA ? - Would two Adcom GFA 555s ran biamped per set of speakers be sufficient, that would be 400 watts RMS going to each speaker.

I have plenty of Adcom GFA 555 and Adcom GFA 5500 amps, also have 3 ea Nakamichi PA amps [ the PA7s can not be bridged ] but being of the STASIS design should offer a little more thump than the Adcoms.

I am overseas in Afghanistan for the next 6 months, but have all this equipment in my house I just bought - trying to get the ideal power solution and would love to meet the 1000 watt per channel rating of these speakers.

Why 800 wpc? How did you come to that number? Watts don't mean a thing, beyond winning an SPL war.

The Adcoms have more "slam" than the PA7, but the PA7 is more refined and has a midrange liquidity that is better than the Adcom 555.

The above statement is assuming the amps are operating at factory spec, which you can never assume for an almost 20 year old amp.

H9

heiney9

F1nut wrote: »

Pro amps are built for power, not high fidelity.

newrival wrote: »

Not true.

Actually it is true

H9

heiney9

newrival wrote: »

Pro amps do often have a common characteristic of being highly detailed, and neutral to the nth degree.

That has to be one of the funniest things I've read in awhile

H9

newrival

I do like Zingo's recommendation for the W4S amp, however, I would not recommend putting that Class D Audio on your SRSes. I have experienced heavy channel drop out on that amp well below reference level when it encounters tougher loads, which the SRSes will definitely provide in a spirited screening.

newrival

heiney9 wrote: »

That has to be one of the funniest things I've read in awhile

H9

Funny or not, it is true. Aside from power, it is the singular goal.

heiney9

Right, complex circuits, lots of negative feedback inexpensive parts and poor design = detail and dead neutral.

Again, I got a chuckle.

If it floats your boat, great enjoy. But pro-amps typically aren't intended nor designed for ultimate fidelity in a serious audio rig.

newrival

heiney9 wrote: »

Actually it is true

H9

Absolutely absurd!

Then explain to me the Bryston SST Pro amps. The Muse 100 was a fanless pro amp, and highly regarded in the audiophile world. Crown had a <$3000 pro amp that was lauded by audiophiles. You speak in broad sweeping generalizations that are patently false. Do you suppose all these amplifiers achieved high fidelity by accident?

heiney9

You do as well (speak in broad sweeping generalizations) From the tone of the OP's question and since he asked about "commercial amps" I surmized he wasn't talking about spending $2-5K on an amp. But more the standard commercial amps you find at a place like Guitar Center or other pro-DJ music outlets.

If that assumption is incorrect then the OP needs to be much more specific about his needs. Here's his direct quote

cobramatteo wrote:

Seems like it might be a great solution to those needing big power on a low budget

Doesn't sound like he's in the market for a $2-5K "pro" amp as you seem to assume.

So in the scope of this thread, I stand by my comments, opinions and experience's. You seem to be talking about expensive higher end amps one might use in a professional recording studio setting, not a commercial amp you might find at a typical low rent night club. That's what I believe the OP is referring to.

H9

Oldmanind

I have used a Yamaha pc2602 on my sda srs 2 with great results. It has a built in fan but has never came on.

F1nut

Funny thing about the folks that use or think about using PA amps, they don't seem to use or think about using PA speakers. I mean, if those PA amps are so damn good, those PA speakers must be just as good, right?

So how about it you PA amp users, why aren't you using PA speakers?

F1nut

That's your rig....really?

zingo

newrival wrote: »

I would not recommend putting that Class D Audio on your SRSes. I have experienced heavy channel drop out on that amp well below reference level when it encounters tougher loads, which the SRSes will definitely provide in a spirited screening.

Please do tell. I've tried their amps on tough loads including LSi15s and Carver ALIIIs with no issues, but I know every amp has a weakness.

newrival

heiney9 wrote: »

Why 800 wpc? How did you come to that number? Watts don't mean a thing, beyond winning an SPL war.

The Adcoms have more "slam" than the PA7, but the PA7 is more refined and has a midrange liquidity that is better than the Adcom 555.

The above statement is assuming the amps are operating at factory spec, which you can never assume for an almost 20 year old amp.

H9

h9, I think you have tremendous wealth in experience and knowledge as far as stereo listening goes, I really do (excluding your views on subwoofers ), but I think it doesn't transition well into HT, especially when it comes to a dedicated HT system.

If he wants to achieve a reference - or near reference - cinema level, Watts mean quite a bit. Especially considering it seems he has a large room and the seating will potentially be quite far from the speakers. This means peaks of 115db at the LP with 3db of headroom. The only way to achieve this is through wattage. Considering he is looking to use his SRSes up front (91db sensitivity), and assuming a LP of 4 meters, even if he fed the speaker the max recommended power handling of 1000W, he would only achieve 109db with 3db of headroom. Of course, that doesn't account for room gain, so presumably, he should be able to reach reference levels near the required headroom with a 1000W amp.

While I agree Wattage isn't everything, saying "watts don't mean a thing," is laughable. This isn't about an SPL contest, it is about creating the cinema experience at home, just like stereo is recreating the live listening event at home. There is some overlap, but your stereo mantras do not apply hear.

A thought occurs to me, though. I have my doubts that the 25-year-old Polks will play that loud without some terrible distortion. I could be quite wrong here, but that is my suspicion.

newrival

zingo wrote: »

Please do tell. I've tried their amps on tough loads including LSi15s and Carver ALIIIs with no issues, but I know every amp has a weakness.

On my emerald physics, the amp sounds great. I've had no issues. While the Legacy Focus was here, big issues. I thought my MIT speaker wire was acting up again, as it did from the factory until i re-terminated the cable, until I noticed the lights on the front blink out. Erniejade witnessed this several times. This was far below HT reference level. I have seen the focus impedance graph and know there are plenty of wild dips, so this was my suspicion. It was confirmed by Class D Audio that that was exactly what I was experiencing. I had no issues while it was playing softer of course, but when slightly demanding, the channels would just drop out. Great amp otherwise.

newrival

deleted

zingo

Good to know. I was able to crank the LSi15s fed by a passive pre with no problem, but all speakers are different, and Legacy's are a beast.

Thanks for the details!

naturallight

Well i do have to say..wow..thats your setup...man i think you need to spend a few bucks and get stuff set up right. Thats pretty nasty.



Now to get back to "commercial" stuff..well. I have a QSC GX5 power amp..it dose run a class "H" type power supply. 500watts per@ 8 ohms. Not sure if that makes the difference or not.



Now the sad point is..I don't find this amp to be bad running a set of SDA 1C's....It's not kicking me in the face with bad sound..the SDA's don't seem to mind it. I can't tell you the difference between that and a high dollar Onkyo..pretty much because it takes me too long to change out the amps. But to be blunt..there is nothing that i can say, off the top of my head, that this QSC amp sounds like crap in. It is does not blow you in the face with crap sound. I don't know what other speakers would sound like, except RTi 12's don't like it, and come across as to bright...but thats what alot of people say about them, with any amp..so may not be a great conclusion.



Now i'm running this in a large room 17x30 and i sit 15 feet back..so these speakers are turned up at a good volume. If your running this in a smaller room, with the speakers closer, and the volume down....then yes, the amp could sound like crap..don't know.



I'm not saying this is right or wrong..and again "ONLY" my opinion.

heiney9

naturallight wrote: »

Well i do have to say..wow..thats your setup...man i think you need to spend a few bucks and get stuff set up right. Thats pretty nasty.



Now to get back to "commercial" stuff..well. I have a QSC GX5 power amp..it dose run a class "H" type power supply. 500watts per@ 8 ohms. Not sure if that makes the difference or not.



Now the sad point is..I don't find this amp to be bad running a set of SDA 1C's....It's not kicking me in the face with bad sound..the SDA's don't seem to mind it. I can't tell you the difference between that and a high dollar Onkyo..pretty much because it takes me too long to change out the amps. But to be blunt..there is nothing that i can say, off the top of my head, that this QSC amp sounds like crap in. It is does not blow you in the face with crap sound. I don't know what other speakers would sound like, except RTi 12's don't like it, and come across as to bright...but thats what alot of people say about them, with any amp..so may not be a great conclusion.



Now i'm running this in a large room 17x30 and i sit 15 feet back..so these speakers are turned up at a good volume. If your running this in a smaller room, with the speakers closer, and the volume down....then yes, the amp could sound like crap..don't know.



I'm not saying this is right or wrong..and again "ONLY" my opinion.

That's cool and it's not my intention to crap on people's gear, but I do have to ask what other amps and gear have you compared the QSC to? The reason I ask about "gear" and not just amps is because all your gear creates synergy.

To my friend Newrival, I'll go with your HT comment except I used to sell HT in the early days and I have several friends who have high quality power, not quantity power and their HT's have incredible dynamics with a lot less than an 800wpc pro-amp. But there is truth to what you say. But again we are all making assumptions as the OP hasn't given near enough information to make a recommendation one way or the other, hence my asking the questions.

H9

motorstereo

Having been there and done that with pro amps on sda's all I can say is don't waste your time with them. Yes they'll get the job done and yes they'll drive the sda's without breaking a sweat. But put a more refined amp on those sda's and you'll be rewarded with better sound and more importantly a bigger and more well defined soundstage.

naturallight

H9, I'm just running the Jolida CD, Adcom pre and normally i run an Onkyo M-504 power amp. This was a test and nothing more.
The QSC has this "H" system power amp...now maybe this could be why it does not sound that bad. Don't know.
It just did not slap me in the face as being bad....i had a hard time trying to find alot of faults with it. But again..it takes me too long to change out this stuff...so for sure was not a switch different amps in 2 seconds...LOL
All i can say ..is it's not the worst amp i have heard.....

naturallight

Normally H9..i would be telling you..all these "commercial" amps are all junk..just massive power, sound like crap. THIS QSC amp....just does not do that. It should have been blowing the stock SDA 2000 tweeters..and making my ears bleed. It did not. In fact, with the SDA 1C's...they liked this amp...I did not find any up front fault with the dam amp. I'm sure if i could switch amps like in a listening studio...i could find some faults with it.



I don't know really what to tell you....I thought it would be a massive difference..no problem...QSC was just a nice pro amp..but again..not the case.



I have no under standing why this should work...All i can tell you is what i heard...and this is "ONLY" my opinion on the sound...

newrival

heiney9 wrote: »

But again we are all making assumptions as the OP hasn't given near enough information to make a recommendation one way or the other, hence my asking the questions.

H9

You are definitely correct about that. Some more information would be helpful. But then how would we ever get through our day? what with no ambiguity to argue over :cheesygrin:

newrival

One thing I can say is that perhaps us arguing on so general a topic as pro amps is as misleading as if we were just talking about amps made in china, or some such thing. There is far too much variance to say pro amps, or chinese amps, or whatever, to say make any general qualitative statements.

h9, your point is well taken about PA amps, and I do realize these fall under the pro umbrella. Often times those are made solely for wattage concerns.

I have heard great things about QSC, but have never heard them personally. I recently did a 3 hour demo of a system driven by high-power behringer amps and I was quite impressed with their musicality.