Can you hear a difference in Sound between Audio Amplifiers?

[Grador]

Listening doesn't stop at our less sensitive ears, they're hard wired to our brains. Years of experience and interpretations have accumulated and heavily influence what we think we are hearing. We don't really "listen with our ears" so much as we do with our brains.

I was using "ear" as a shorthand for our sense of hearing as a general concept.

 

[DD66000]

Sure, it can be for you. If it wasn't for scientists/engineers who have to prove everything beyond their senses, we wouldn't be able to enjoy our hifi gear now.

Of coarse they test speakers and amps, but at least in the case of speakers, if the Harman engineers do not like the final outcome during a listening test, they go back to the drawing board.

There are many different frequency response parameters, like into different power levels or into different loads, or even with different input loads. Frequency response curves are also measured by doing a spectrum sweep, which is one frequency at a time. Amplifier performance gets a lot more interesting with complex input loads. These days I expect any well-designed amplifier, tube or solid state, to have a flat 1W frequency response curve into 8 ohm loads. Since they're all pretty much the same these curves are not very telling at all.​

Exactly

Or not. Dr. Rich has examined different topologies many years ago and how components sound.

And I suppose nothing has changed in the years since as in better designed circuits or higher quality components. If that is what you think, then you are lost.

Well, a few amps can sound different, but the only way to find out if one wants to know is a controlled test, period.

Well, the Panasonic amp in that article that was used was so bad, it was more than obvious. There are amps so bad on the HF that they can grate your ears off...then change to another amp and all is good again.
JBL speakers are known not to be laid back on the top end. Connect them to the wrong amp, better be wearing ear plugs. Connect an amp that smooths instead of exasperates the HF and its beautiful music. Been there, Done that!!

I've also experienced just the opposite as well, laid back speakers connected to an amp that was soft on the HF and the result was lifeless sound.

 

[Grador]

JBL speakers are known not to be laid back on the top end. Connect them to the wrong amp, better be wearing ear plugs. Connect an amp that smooths instead of exasperates the HF and its beautiful music. Been there, Done that!!

I've also experienced just the opposite as well, laid back speakers connected to an amp that was soft on the HF and the result was lifeless sound.

Those sound like amps with design failings though. No one has argued that there are not poorly designed and executed amplifiers. The question seems to be more of asking if amplifiers without any obvious faults really impart a character onto sound.

 

[AcuDefTechGuy]

I was using "ear" as a shorthand for our sense of hearing as a general concept.

Well, the brain won't hear anything if the ears are dysfunctional.

Guess we need both.

 

[mtrycrafts]

And I suppose nothing has changed in the years since as in better designed circuits or higher quality components. If that is what you think, then you are lost.

....

Interesting. So then, when that paper and examination of all the different topologies with no audible differences were done , we must have evolved our hearing sense since to the point that today we can hear sooo much better that now we can hear differences due to parts and topologies???? I am pretty sure that it is you who is lost.

Oh, yes, I'd like to see those FR specs with full power, 20-20kHz.

 

[DD66000]

Those sound like amps with design failings though. No one has argued that there are not poorly designed and executed amplifiers. The question seems to be more of asking if amplifiers without any obvious faults really impart a character onto sound.

As that article mentioned, if an amp FR tilts in either direction, then you get a change in sound. If the HF is +1db compared to another amp that is maybe -1db @ HF then the HF is being exasperated and connected to a pair of speakers that do not roll off the high end (not laid back) then you have a problem of the HF being over emphasized, thus sounding harsh. So that fact does not mean that the amp is a bad design, just that it needs laid back speakers.

 

[DD66000]

Interesting. So then, when that paper and examination of all the different topologies with no audible differences were done , we must have evolved our hearing sense since to the point that today we can hear sooo much better that now we can hear differences due to parts and topologies???? I am pretty sure that it is you who is lost.

Oh, yes, I'd like to see those FR specs with full power, 20-20kHz.

And you are side stepping the fact that what was in the '50s, '60s, '70s may not apply to today's technology. Look at capacitors, Polypropylene and Polystyrene produce slightly different sounds. Polystyrene caps, when used as by-pass caps in the HF circuit of a XO produces a more open, airy sound. Whereas using Polypropylene by-pass caps produce more of a dynamic sound. And those caps did not exist 1/2 a century ago.

 

[Irvrobinson]

As that article mentioned, if an amp FR tilts in either direction, then you get a change in sound. If the HF is +1db compared to another amp that is maybe -1db @ HF then the HF is being exasperated and connected to a pair of speakers that do not roll off the high end (not laid back) then you have a problem of the HF being over emphasized, thus sounding harsh. So that fact does not mean that the amp is a bad design, just that it needs laid back speakers.

Can you show us an example of a solid state amplifier which exhibits a measured frequency response that tilts as you describe?

The situation I see is that most amps are so well-behaved in static testing for frequency response that the measurement has become almost useless in differentiating them.

 

[cpp]

Can you show us an example of a solid state amplifier which exhibits a measured frequency response that tilts as you describe?

I would like to see that as well..

 

[Irvrobinson]

And you are side stepping the fact that what was in the '50s, '60s, '70s may not apply to today's technology. Look at capacitors, Polypropylene and Polystyrene produce slightly different sounds. Polystyrene caps, when used as by-pass caps in the HF circuit of a XO produces a more open, airy sound. Whereas using Polypropylene by-pass caps produce more of a dynamic sound. And those caps did not exist 1/2 a century ago.

Ah yes, the audiophile capacitors-sound-different proposition. To be honest, I've always thought this ranked right up there with the cable lie. What are a capacitor's electrical parameters that yield an open, airy sound, versus sound that is merely dynamic?

 

[Steve81]

Can you show us an example of a solid state amplifier which exhibits a measured frequency response that tilts as you describe?

The Behringer A500 comes to mind as having a slightly rolled off top end (-0.6dB @ 20kHz), with 1 watt into an 8 ohm resistive load. One wonders what might happen to the FR if those conditions change, i.e. trying to drive a speaker with something akin to this impedance profile at higher volumes:

 

[Steve81]

What are a capacitor's electrical parameters that yield an open, airy sound, versus sound that is merely dynamic?

$$$ per Farad, duh

 

[Irvrobinson]

The Behringer A500 comes to mind as having a slightly rolled off top end (-0.6dB @ 20kHz), with 1 watt into an 8 ohm resistive load. One wonders what might happen to the FR if those conditions change, i.e. trying to drive a speaker with something akin to this impedance profile at higher volumes:

I'm assuming you got that -0.6db from the Audio Critic's test report, which is out of date. The newer version of this amp has completely different specs. Nonetheless, one point for you, although I doubt a departure from flatness like that would be audible for most of us, even some young squirt like Monkish54. And static frequency response measurements don't necessarily tell you a lot about how an amp's output will change with a complex load.

 

[Steve81]

I'm assuming you got that -0.6db from the Audio Critic's test report, which is out of date. The newer version of this amp has completely different specs. Nonetheless, one point for you, although I doubt a departure from flatness like that would be audible for most of us, even some young squirt like Monkish54.

You won't get an argument from me there.

(Edited this part as I mis-read the "one point for me" bit).

And static frequency response measurements don't necessarily tell you a lot about how an amp's output will change with a complex load.

Again, no argument from me; in fact, that's rather the point of my post. We know how the old A500 performs into an 8 ohm resistive load at 1 watt, but that doesn't guarantee results when something a little less amplifier friendly comes along and the output levels get jacked up a couple notches.

 

[3db]

[/B]

And there lies your problem. Harman has the most advanced testing facility in the world....
But what is the final test for all their speakers...the human ear. That says it all!!

It doesn't say anything at all. For speakers, there is a clearly a difference. For amplifiers operating in their intended design parameters, it says absolutley nothing unless backed up by a blind listening tests where there is a clear choice to the preference of one amp to another.

 

[3db]

Listening doesn't stop at our less sensitive ears, they're hard wired to our brains. Years of experience and interpretations have accumulated and heavily influence what we think we are hearing. We don't really "listen with our ears" so much as we do with our brains.

Exactly. There is so much more than sound energy coming in when we sit and listen. We simply cannot turn of all our other senses for the sake of hearing to determine what is audibly different among amplifiers performing in their intended design parameters. One's mood can especially have an influence on "how" we interpret "what" we hear.

 

[cpp]

Exactly. There is so much more than sound energy coming in when we sit and listen. We simply cannot turn of all our other senses for the sake of hearing to determine what is audibly different among amplifiers performing in their intended design parameters. One's mood can especially have an influence on "how" we interpret "what" we hear.

Yep, tell that to a wife that has PMS, and I can ensure you that can influence "how" we interpret "what" we hear. There is so much more involved that measurements and equipment. The room and it's surroundings have a big impact not to mention the music itself. Crap in, Crap out..

 

[audiovideobob]

Amplifier sound

Hi
I have been in the A/V business since 1977.There has always been a difference in sound between components and cables and always will be. The best way to find out is to change one component or cable in your system with the one in question without changing anything else. Past all the details that will let you know.

 

[3db]

Hi
I have been in the A/V business since 1977.There has always been a difference in sound between components and cables and always will be. The best way to find out is to change one component or cable in your system with the one in question without changing anything else. Past all the details that will let you know.

I guess you aren't influenced by sight bias or by the affliction of accurate short term memory that is typical of the general populous.

 

[j_garcia]

Hi
I have been in the A/V business since 1977.There has always been a difference in sound between components and cables and always will be. The best way to find out is to change one component or cable in your system with the one in question without changing anything else. Past all the details that will let you know.

I HAVE changed single items in my systems over the last 20+ years and while some components definitely make a difference I haven't found any cables that really made a big difference. So yes, it did let me know