Any pro amps with 200-500 w/ch and > 115db s/n ratio (at rated power)? - Page 2 - AVS Forum
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post #31 of 39 Old 03-25-2013, 07:06 AM
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I have used Sherbourn, Ada, and Nakamichi amps on my 109 dBs sensitive speakers with no problems.
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post #32 of 39 Old 03-25-2013, 12:30 PM
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Quote:
Originally Posted by Bigus View Post

Many amps have published snr of mid 90's at 1 watt. Is it that you don't believe them?

Can you post some links to some graph pictures of amps or AVRs that have at or beyond 115 SNR?
Or even some graphs that meet their whitepaper spec?

Preferably from an independent third-party lab (not cooked books), and cost less that 2 grand
and have a second harmonic at the test frequency below 96db.
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post #33 of 39 Old 03-25-2013, 01:04 PM
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Quote:
Originally Posted by BassThatHz View Post

Quote:
Originally Posted by Bigus View Post

Many amps have published snr of mid 90's at 1 watt. Is it that you don't believe them?

Can you post some links to some graph pictures of amps or AVRs that have at or beyond 115 SNR?
Or even some graphs that meet their whitepaper spec?

Preferably from an independent third-party lab (not cooked books), and cost less that 2 grand
and have a second harmonic at the test frequency below 96db.

??

I was simply responding to your claim that if some esoteric amp had 1 watt SNR of 90dB, then it "basically can't be done."

Simple question, is it that you don't believe the published specs? That's fine if you don't, but it's your problem and you'll have to find independent third party "graphs" that satisfy yourself and meet your criteria, now at 115 not >90 (still talking about 1 watt???).

But if you're willing to trust published "cooked books" then Emotiva offers several amps with 1 watt SNR >>90dB and cost less than $2k. Take your pick. They certainly aren't the only options either.

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post #34 of 39 Old 03-25-2013, 08:23 PM
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bigus, bassthathz,

there are several ways of specifying signal to noise ratio with a big difference being if it is at 1w or "below full power". if at full power, you have to subtract the amount of the power for comparability.

example: the mark levinson no. 53 s/n is rated at -85db and the behringer ep4000 is rated at -100db.

so how does behringer beat mark levinson?

the ml amp is at 1 watt. the ep4000 is at rated power, which is 450 watts. 450 watts is 26.5db higher than 1w, so subtract that off the behringer. the behringer is now at -73db s/n, which is 12db less quiet than the mark levinson.

a weighting, no-weighting, 20hz-20khz or 1khz, use of the "greater than sign", are also other ways of confusing the matter.

so, just be careful when making "quick comparos" with respect to s/n ratio.

Listen. It's All Good.
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post #35 of 39 Old 03-26-2013, 07:28 AM
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Originally Posted by LTD02 View Post

bigus, bassthathz,

there are several ways of specifying signal to noise ratio with a big difference being if it is at 1w or "below full power". if at full power, you have to subtract the amount of the power for comparability.

example: the mark levinson no. 53 s/n is rated at -85db and the behringer ep4000 is rated at -100db.

so how does behringer beat mark levinson?

the ml amp is at 1 watt. the ep4000 is at rated power, which is 450 watts. 450 watts is 26.5db higher than 1w, so subtract that off the behringer. the behringer is now at -73db s/n, which is 12db less quiet than the mark levinson.

a weighting, no-weighting, 20hz-20khz or 1khz, use of the "greater than sign", are also other ways of confusing the matter.

so, just be careful when making "quick comparos" with respect to s/n ratio.

Exactly. The published specs mean nothing. I've even seen some pro amps that use a noise gate at idle which can give a very nice idle S/N but not necessarily what you want.

If you want low noise do three things. First, make sure you don't have ground loop issues. Second, make sure your amps are in good working order. Third, setup your gain structure properly.
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post #36 of 39 Old 03-26-2013, 08:20 AM
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I have bought many used amps and some have a hiss and others don't, usually it has nothing to do with the S/N ratio but leaky capacitors or bad resistors and once repaired they all become silent.
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post #37 of 39 Old 03-26-2013, 03:45 PM - Thread Starter
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Thanks for all the suggestion guys. I ended up getting a very good deal on an ATI 2007 amp. 100lb beast with 200 watts and seven channels. No fans to deal with, claimed s/n ratio of 120db (their cheaper amps have a 105db s/n ratio so maybe we can trust the specs?). Balanced and single ended inputs. Each of the seven channels has fully balanced circuitry. So basically this amp has fourteen 100 watt amps inside. eek.gif It also comes with a 7 year warranty and is made in the USA. Too many reasons not to get it, though I wonder if there is any real benefit to fully balanced circuitry when it's feed from a single ended pre-pro?

Being fan-less I can stick this guy behind the screen to feed all 7 of 11 channels up front.

Quote:
Originally Posted by coctostan View Post

I've even seen some pro amps that use a noise gate at idle which can give a very nice idle S/N but not necessarily what you want.

Initially I was using a dbx drive rack pa+ to boost the -10dbu signal to +4. Every time there was a gap between songs, you could hear the muting circuit kicking in. VERY annoying, the original drive rack didn't do that.

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Originally Posted by MKtheater View Post

I have bought many used amps and some have a hiss and others don't, usually it has nothing to do with the S/N ratio but leaky capacitors or bad resistors and once repaired they all become silent.

Those noisy XLS's were all bought new. I had five of them at one stage and they all had the same issue with hi-efficiency speakers. They were fine on normal speakers. Possible they all had the same fault from the factory I guess.
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post #38 of 39 Old 03-26-2013, 04:26 PM - Thread Starter
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Originally Posted by DS-21 View Post


Sherwood Newcastle A-965 on my amp-noise test (Eminence APT tweeter on one of their horns, plugged in), but then again I've not found anything near the price of the A-965 that's as low in self-noise as it is. (Similarly low-noise amps are things like Brystons, Anthem Statements, and McIntoshes.) I'd recommend one for the OP, but they're out of production, and 3dBW less powerful than desired. (Though with 102dB/W/m speakers, 20dBW of power with 1.5dB headroom per channel should be more than sufficient domestic audio use....)

The A-965's look like a great deals used on ebay. 100 watts would be plenty for movies, but I was able to clip the 90w/ch Crown CP660 playing CD's. Not that I would play at those volumes (115db peaks from the speakers at the seats 20 ft away) for more than a song or two.

I might try one of those A-965's for the surrounds.
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post #39 of 39 Old 03-26-2013, 04:27 PM - Thread Starter
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Originally Posted by MKtheater View Post

I have used Sherbourn, Ada, and Nakamichi amps on my 109 dBs sensitive speakers with no problems.

What speakers are you running now? Last time I was following along it was the JBL's and the the BFM's
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