Can we really hear a difference between amps? - Page 51 - Home Theater Forum and Systems - HomeTheaterShack.com

View Poll Results: Is there a noticeably audible difference between two level matched solid state amps under controlled
Yes... I believe a notable difference can be heard. 136 48.57%
No... I do not believe there is any audibly significant difference. 144 51.43%
Voters: 280. You may not vote on this poll

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post #501 of 825 Old 08-29-13, 10:50 AM
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Re: Can we really hear a difference between amps?

I don't know if it's something that has been measured, but one thing I can think of is how the feedback circuit(s) in an amplifier stage might effect the phase at different frequencies. You could also have different amounts of distortion at different frequencies, though whether this has an audible effect I don't know, but I'm just pointing out some areas of possible technical differences between otherwise similarly specified amplifiers. There are lots of other things we could measure (or come up with ways to measure) other than the standard S/N, % THD and frequency response which might help explain why some feel that amplifiers sound different,so I feel that just using those measurements isn't necessarily capturing all that the amplifier does to the signal.

I have to confess two things:

1. I used to build, service and repair amplifiers for a living, though they were for Armed Forces rather than 'hifi' amplifiers, so the testing we did as part of QC was purely the basic frequency response and output/distortion check at 1Khz.

2. I run separate power amplifiers in my set up since I have an AV processor, so they are necessary. I did add a second power amp so I could bi amp my front three speakers and I felt it was worthwhile, though of course it could be placebo...I do tend to listen at pretty high levels (-5dB below reference usually) though my speakers aren't particularly hard to drive/inefficient.
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post #502 of 825 Old 08-29-13, 02:19 PM
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Re: Can we really hear a difference between amps?

We really can't hear phase alignments unless the phase is different on each side of the system or in each ear. It would be pretty abnormal to encounter an amp with misaligned phase on each channel. But, if you did, I think it would be audible as would any number of other defects in an amplifier. Distortion does indeed vary with frequency but as long as it is under 1% we can't hear it so it isn't important. My point is that modern HiFi amps basically sound the same as long as they are working correctly and within their design parameters.
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post #503 of 825 Old 08-29-13, 02:51 PM
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Re: Can we really hear a difference between amps?

Then we shall agree to disagree. I'm very reluctant to return to using a receiver rather than pre pro set up, but I do like to listen at higher levels. Personally I don't believe that one box with all the channels drawing from the same power supply is the best way to reproduce sound. In my own experience trying this way gave a harsh sound at the higher levels I like to listen at, but separate amps didn't.

However, lets just leave it there since I don't want to get into a pointless argument when we both see things differently and won't convince either of the other's view.
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post #504 of 825 Old 08-29-13, 06:53 PM
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Re: Can we really hear a difference between amps?

Sorry, I assumed from the title of the thread that the participants wanted to discuss amplifier audibility. I misunderstood. Take care.
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post #505 of 825 Old 08-30-13, 02:50 AM
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Re: Can we really hear a difference between amps?

I did, but I just can't see us agreeing on anything, so it's pretty pointless to continue and I haven't the time or inclination to argue further. Just remember that a lot of audio measurements are done using a simple sine wave and not the complex waveforms of music, so IMHO some of the standard measurement techniques don't capture and/or explain everything.

Take care.

Last edited by KelvinS1965; 08-30-13 at 10:54 AM.
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post #506 of 825 Old 09-10-13, 08:45 AM
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Re: Can we really hear a difference between amps?

I had a Yamaha amp running off a Yamaha receiver, and noticing at higher volumes, the sound quality suffered greatly. After reading threads like this, posting questions, and more research, one of the amps I had been pointed towards came up for sale used, so I figured I'd try it. Nothing else changed, it was just pull out one 2 channel amp, plug in another, both rated at 150wpc. Not a scientific A-B, nothing like that, just 'lets see if this helps'. It did, massively. The speakers are 25 years old, and I've never heard the bass sound as tight and controlled as it did now, and the harsh stridency in the highs was reduced a lot. Even my wife heard a difference, and she's not a 'listener'. It wasn't about volume, it was purely the control and musicality bumped a notch.

No doubt there are the 'you wanted to hear a difference, so you did' naysayers, and that's fine. I'm sure there are technical reasons that could explain the difference, like current capacity, and the 'new' amp is twice the weight of the old one, but the plain truth is that the sound quality improved. I did hope for a difference, but I expected to have to try to listen for it. The purpose was to 'tame' harsh highs at higher volume, but the result was immediately noticeable in the bass - I don't use my sub for 2 channel any more. YMMV, IMHO, etc, etc
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post #507 of 825 Old 09-10-13, 12:16 PM Thread Starter
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Re: Can we really hear a difference between amps?

The older Yamaha may very well not have been rated as accurately as the newer amp... may not have been designed to drive your particular speakers... could have been faulty, may have had a different frequency response, etc., etc. There are a number of variables that could be causing the difference. Obviously there was some type of design difference (or issue) if you noticed a dramatic change. It would not necessarily surprise me that some newer amps sounded better than some older amps... all depending on who made them and when they were made. I don't think that has ever really been questioned.
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post #508 of 825 Old 09-11-13, 07:35 AM
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Re: Can we really hear a difference between amps?

The amp I had been using was one I'd used since I got the speakers. The system was essentially unchanged all that time, since the late 80's. I got a deal on the receiver, and hooked it up to the speakers alone at first, then re-added the amp to the system, and didn't hear much difference. This was before I added any surround speakers, so the amp and receiver were both only driving the mains. Both rated at 150wpc. That was partly why I wasn't expecting much improvement with the 'new/used' amp, but there was. I don't believe the original amp was 'defective' in any way, or not working properly, but obviously I can't be sure it still measured up to it's original specs. It did at least equal the new receiver, though.

As I said, this wasn't a specific test, designed to find out if I could hear a difference. I was looking for a solution to the problem, and tried the amp, and got a bigger benefit than I expected. The area I was 'looking' for improvement was the highs, which I got, but the dramatic difference was in the bass. So for me, the question of 'can you hear a difference between amplifiers' is a resounding yes, however I would also say that if you have 2 new amps of similar specs and price points, I wouldn't want to bet on hearing a difference....I guess it's a question of thresholds - and perhaps each person has a different threshold of audibility, just as we have different thresholds of pain...??
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post #509 of 825 Old 09-11-13, 10:06 AM Thread Starter
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Re: Can we really hear a difference between amps?

Yeah... it was not just a general question, it was qualified. If you are hearing dramatic differences, then something was likely array if you had two good quality amps with basically the same specs.

From all that I can gather, even the golden ear guys will admit that the differences they claim they hear between two different amps are very subtle... not dramatic. Of course several well conducted double blind listening tests suggest that those differences cannot be identified, even by some golden ear guys. Yet, there are those that have never participated in DBT that suggest there are differences, but not dramatic.

I can't say one way or another with 100% certainty between two quality amps, other than I can say that I have never been able to pin point any particular differences, unless the amp was simply unable to power inefficient speakers (I have certainly heard that difference and it was indeed dramatic and extremely noticeable distortion). I think the only way I could ever prove it for certain to myself would be in a DBT. Then there are those that suggest some differences we hear can't be tested, but again, they are very subtle differences, not dramatic. I think in all cases, dramatic differences can be tested and identified.
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post #510 of 825 Old 09-11-13, 10:24 AM
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Re: Can we really hear a difference between amps?

Quote:
Sonnie wrote: View Post
I think the only way I could ever prove it for certain to myself would be in a DBT. Then there are those that suggest some differences we hear can't be tested, but again, they are very subtle differences, not dramatic. I think in all cases, dramatic differences can be tested and identified.
Not sure if this has been suggested already but what about a Home Theater Shack DBT of some popular amps? Along the lines of the recently completed speaker shootout. I've always been curious about this myself. I am somewhat convinced I have heard differences between similarly spec'd amps, but have never done a DBT, which I agree would be the only way to really tell.
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