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Why amplifiers sound the same

So I've been studying amplifier design in the last several weeks and I think I understand why amplifiers are supposed to sound the same. This is my explanation.

Amplifiers amplify voltage and the load impedance, in accordance with Ohms Law, must draw a current up to the limits the amplifier can supply, which can vary if the nut holding the volume control goes overboard, so assuming the amp was operating within clean limits (not clipping) the noise and distortion can be expected to be inaudible.

Solid-state amplifiers in general all seem to have similar frequency response (flat) and exhibit very low output impedance, which means they are largely load intolerant so the frequency response is likely to remain unaffected, unlike a switch-mode or valve amplifier which can affect the frequency response in very audible ways due to their high output impedance.

It is well known that a change in loudness between two components can affect how one interprets the sound of that component. A small difference (1-2 dB) may lead to different sonic characteristics (enhanced dynamics, additional 'richness', 'texture', improved sound staging, speakers 'singing', etc), which is guaranteed to happen in casual comparisons.

So the operating assumption is that if two amplifiers are working within clean limits (ie not clipping), with levels carefully matched to within +- 0.1 dB (a multimeter is required), in blinded conditions so that any biases from the listener (knowingly, or unknowingly) do not contaminate the listening, the amps will sound the same.

This has been the default position for over 40 years supported by mountains of audibility reports in double blind testing. Now in casual comparisons, most of these assumptions are thrown out the window. Audiophiles rarely if ever compare two amplifiers in the same conditions, set up the same way. They are likely to compare two amplifiers at different volume levels, at different times, with various expectations/biases in place fostered by magazine reviews, what the salesperson said in the showroom etc.

So if the goal was to 'just listen', without peeking, and assuming two amps were operating within clean limits, the expected result, as confirmed by science, is that two amplifiers will not and should not sound audibly different.

Am I correct in the points I've made, or have I left anything out?

Why amplifiers sound the same

Reply #1 –
Quote from: Rich B on
So I've been studying amplifier design in the last several weeks and I think I understand why amplifiers are supposed to sound the same. This is my explanation.


You seem to miss the most important point right from the start: Amplifiers are supposed to sound the same so that they don't get in the way of experiencing the "true" sound of the audio that passes through it. There is only one way the sound can be true to the original, therefore the closer the amplifiers come to this ideal, the more they sound the same. In other words: It is a rational and deliberate design goal to make amplifiers sound the same. This goal is reasonable, and the technology is well researched and quite capable of fulfilling this goal without much expense or difficulty.

Quote
Amplifiers amplify voltage and the load impedance, in accordance with Ohms Law, must draw a current up to the limits the amplifier can supply, which can vary if the nut holding the volume control goes overboard, so assuming the amp was operating within clean limits (not clipping) the noise and distortion can be expected to be inaudible.


Yes, provided the amplifier is designed with the above goal in mind.

Quote
Solid-state amplifiers in general all seem to have similar frequency response (flat) and exhibit very low output impedance, which means they are largely load intolerant so the frequency response is likely to remain unaffected, unlike a switch-mode or valve amplifier which can affect the frequency response in very audible ways due to their high output impedance.


Swichmode or valve amplifiers can also be designed to exhibit low output impedance. It is easier to accomplish with conventional solid state designs, however. Low output impedance is a feature of a certain amplifier design, and not that much a feature of the devices used.

Quote
It is well known that a change in loudness between two components can affect how one interprets the sound of that component. A small difference (1-2 dB) may lead to different sonic characteristics (enhanced dynamics, additional 'richness', 'texture', improved sound staging, speakers 'singing', etc), which is guaranteed to happen in casual comparisons.


This has nothing to do with amplifier design, but with the way they're compared, i.e. the design of a listening test. In other words, it addresses the question why amplifiers appear to sound different, not why they actually sound different.

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So the operating assumption is that if two amplifiers are working within clean limits (ie not clipping), with levels carefully matched to within +- 0.1 dB (a multimeter is required), in blinded conditions so that any biases from the listener (knowingly, or unknowingly) do not contaminate the listening, the amps will sound the same.


No, the working assumption is that amplifiers which actually sound the same, will appear to sound the same if you get your method of comparison right. That involves level matching, blind testing, and so on.

Another working asumption is that amplifiers built by competent people with the above design goal in mind, will actually sound the same.

Quote
This has been the default position for over 40 years supported by mountains of audibility reports in double blind testing. Now in casual comparisons, most of these assumptions are thrown out the window. Audiophiles rarely if ever compare two amplifiers in the same conditions, set up the same way. They are likely to compare two amplifiers at different volume levels, at different times, with various expectations/biases in place fostered by magazine reviews, what the salesperson said in the showroom etc.


Yes. Most people seem to believe that amplifiers actually sound different, when they only appear to sound different because of their flawed way of comparing them.

Quote
So if the goal was to 'just listen', without peeking, and assuming two amps were operating within clean limits, the expected result, as confirmed by science, is that two amplifiers will not and should not sound audibly different.


Yes. If this expected result isn't found in practice, it is an indication of either a fault somewhere, or an indication that the amplifier was not built with the above goal, in which case the deviations from the ideal will be readily measurable.

Quote
Am I correct in the points I've made, or have I left anything out?


You left out a clear distinction between the the properties of the amplifier itself, and the properties of human hearing/psychology with its impact on amplifier comparisons. Those two things are completely different and need to be distinguished to have a meaningful discussion.

Why amplifiers sound the same

Reply #2 –
Quote from: pelmazo on
Quote from: Rich B on
So I've been studying amplifier design in the last several weeks and I think I understand why amplifiers are supposed to sound the same. This is my explanation.

Amplifiers amplify voltage and the load impedance, in accordance with Ohms Law, must draw a current up to the limits the amplifier can supply, which can vary if the nut holding the volume control goes overboard, so assuming the amp was operating within clean limits (not clipping) the noise and distortion can be expected to be inaudible.

Solid-state amplifiers in general all seem to have similar frequency response (flat) and exhibit very low output impedance, which means they are largely load intolerant so the frequency response is likely to remain unaffected, unlike a switch-mode or valve amplifier which can affect the frequency response in very audible ways due to their high output impedance.

It is well known that a change in loudness between two components can affect how one interprets the sound of that component. A small difference (1-2 dB) may lead to different sonic characteristics (enhanced dynamics, additional 'richness', 'texture', improved sound staging, speakers 'singing', etc), which is guaranteed to happen in casual comparisons.

So the operating assumption is that if two amplifiers are working within clean limits (ie not clipping), with levels carefully matched to within +- 0.1 dB (a multimeter is required), in blinded conditions so that any biases from the listener (knowingly, or unknowingly) do not contaminate the listening, the amps will sound the same.

This has been the default position for over 40 years supported by mountains of audibility reports in double blind testing. Now in casual comparisons, most of these assumptions are thrown out the window. Audiophiles rarely if ever compare two amplifiers in the same conditions, set up the same way. They are likely to compare two amplifiers at different volume levels, at different times, with various expectations/biases in place fostered by magazine reviews, what the salesperson said in the showroom etc.

So if the goal was to 'just listen', without peeking, and assuming two amps were operating within clean limits, the expected result, as confirmed by science, is that two amplifiers will not and should not sound audibly different.

Am I correct in the points I've made, or have I left anything out?



Do you still feel I'm a concern troll, or someone who is starting to veer in the direction of objectivity? I've been trying lately, so I hope you think better of me.

Why amplifiers sound the same

Reply #3 –
Quote
Do you still feel I'm a concern troll, or someone who is starting to veer in the direction of objectivity? I've been trying lately, so I hope you think better of me.


I just hit the wrong button, sorry for the block quote. See my modified post.

Apart from this, I still think that you learn very little from the discussions that you have had here for many months. This stuff has been explained many times, yet you manage to get even the fundamentals wrong.

Why amplifiers sound the same

Reply #4 –
Quote from: Rich B on
So I've been studying amplifier design in the last several weeks and I think I understand why amplifiers are supposed to sound the same. This is my explanation.

Amplifiers amplify voltage and the load impedance, in accordance with Ohms Law, must draw a current up to the limits the amplifier can supply, which can vary if the nut holding the volume control goes overboard, so assuming the amp was operating within clean limits (not clipping) the noise and distortion can be expected to be inaudible.

Solid-state amplifiers in general all seem to have similar frequency response (flat) and exhibit very low output impedance, which means they are largely load intolerant so the frequency response is likely to remain unaffected, unlike a switch-mode or valve amplifier which can affect the frequency response in very audible ways due to their high output impedance.

It is well known that a change in loudness between two components can affect how one interprets the sound of that component. A small difference (1-2 dB) may lead to different sonic characteristics (enhanced dynamics, additional 'richness', 'texture', improved sound staging, speakers 'singing', etc), which is guaranteed to happen in casual comparisons.

So the operating assumption is that if two amplifiers are working within clean limits (ie not clipping), with levels carefully matched to within +- 0.1 dB (a multimeter is required), in blinded conditions so that any biases from the listener (knowingly, or unknowingly) do not contaminate the listening, the amps will sound the same.

This has been the default position for over 40 years supported by mountains of audibility reports in double blind testing. Now in casual comparisons, most of these assumptions are thrown out the window. Audiophiles rarely if ever compare two amplifiers in the same conditions, set up the same way. They are likely to compare two amplifiers at different volume levels, at different times, with various expectations/biases in place fostered by magazine reviews, what the salesperson said in the showroom etc.

So if the goal was to 'just listen', without peeking, and assuming two amps were operating within clean limits, the expected result, as confirmed by science, is that two amplifiers will not and should not sound audibly different.

Am I correct in the points I've made, or have I left anything out?


As far as your discussion goes (and this comment relates to just about everything) it looks pretty good to me.

Why amplifiers sound the same

Reply #5 –
Quote from: pelmazo on
Quote
Do you still feel I'm a concern troll, or someone who is starting to veer in the direction of objectivity? I've been trying lately, so I hope you think better of me.


I just hit the wrong button, sorry for the block quote. See my modified post.

Apart from this, I still think that you learn very little from the discussions that you have had here for many months. This stuff has been explained many times, yet you manage to get even the fundamentals wrong.


Shucks.  :  (

Why amplifiers sound the same

Reply #6 –
Quote from: Rich B on
Quote from: pelmazo on
Apart from this, I still think that you learn very little from the discussions that you have had here for many months. This stuff has been explained many times, yet you manage to get even the fundamentals wrong.


Shucks.  :  (


I guess you should ask yourself what's going wrong here. Your summary of amplifier sound could have been made by an average person after at most a couple of days of forum discussion. If it takes much longer than that, there's some kind of mental blockade, or ideology, in the way.

Why amplifiers sound the same

Reply #7 –
Quote from: Rich B on
Do you still feel I'm a concern troll, or someone who is starting to veer in the direction of objectivity? I've been trying lately, so I hope you think better of me.
You made some good observations in the lower half of your post, I give you that.
It's only audiophile if it's inconvenient.

Why amplifiers sound the same

Reply #8 –
Quote from: Kohlrabi on
Quote from: Rich B on
Do you still feel I'm a concern troll, or someone who is starting to veer in the direction of objectivity? I've been trying lately, so I hope you think better of me.
You made some good observations in the lower half of your post, I give you that.


Thanks, I think I'm starting to make sense of some things. It's taken a long time, and I know I'm not particularly bright on these matters, but some progress is good progress in my book.

Why amplifiers sound the same

Reply #9 –
Quote from: Rich B on
Thanks, I think I'm starting to make sense of some things. It's taken a long time, and I know I'm not particularly bright on these matters, but some progress is good progress in my book.

I don't think this relates primarily to intelligence, and I certainly don't think you are dumb. You do, however, seem to have a real stubborn streak.

One read of the TOS of HA should tell you that any conclusions that have been established in this environment have been well thought-out and argued over the years and can be relied on as being state-of-the-art knowledge. In spite of this you seem to require us to convince you of even the simplest facts as though we were the same as every other web site on the internet in which anyone can express any opinion and not be challenged.

I'm sure that this kind of reluctance to accept what we see in writing results from bad experiences elsewhere. But at HA if something is controversial, you will hear conflicting opinions from various members, and if it is not argued over then you can trust what you read as being reliable.

HA represents the combined knowledge and intelligence of many of the smartest people in audio technology today, so just sit back and learn.

P.S. Thank you for sticking with it instead of just leaving, as many before you have done in the past.

Why amplifiers sound the same

Reply #10 –
Thanks pdq for the encouraging comments. There were many times when I felt like leaving out of frustration and due to impatience, which are all character flaws. Having a relatively short fuse probably doesn't help matters.

Anyway, thanks for the comments.

Why amplifiers sound the same

Reply #11 –
Quote
You seem to miss the most important point right from the start: Amplifiers are supposed to sound the same so that they don't get in the way of experiencing the "true" sound of the audio that passes through it. There is only one way the sound can be true to the original, therefore the closer the amplifiers come to this ideal, the more they sound the same.


Can you please elaborate a bit on what you mean by "true" sound of the audio? You mention only one way the sound can be true to the original. Do you mean original waveform? When you say there is one way for true sound, that the signal must be unaltered on an audible level?

Why amplifiers sound the same

Reply #12 –
Quote from: Rich B on
Can you please elaborate a bit on what you mean by "true" sound of the audio? You mention only one way the sound can be true to the original. Do you mean original waveform?


I'm writing within the context of amplifier design, which is the topic you've raised. This perspective treats the input signal to the amplifier as "the original", which is evidently an electrical waveform.

Quote
When you say there is one way for true sound, that the signal must be unaltered on an audible level?


Yes. Signal alterations which have no audible consequences are generally assumed to be irrelevant.

To provide an example for this: Two amplifiers may differ in their bandwidth, i.e. one amplifier has a passband up to 50 kHz, and the other up to 100 kHz. Both limits are significantly above the audible range. Therefore the difference is regarded as irrelevant for their effect on the sound. If they have no other deficiency, both can be true to the original despite their bandwidth difference.

Why amplifiers sound the same

Reply #13 –
Quote from: Rich B on
Quote
You seem to miss the most important point right from the start: Amplifiers are supposed to sound the same so that they don't get in the way of experiencing the "true" sound of the audio that passes through it. There is only one way the sound can be true to the original, therefore the closer the amplifiers come to this ideal, the more they sound the same.


Can you please elaborate a bit on what you mean by "true" sound of the audio? You mention only one way the sound can be true to the original. Do you mean original waveform? When you say there is one way for true sound, that the signal must be unaltered on an audible level?


It must be true to the captured and encoded sound wave and reproduce it as faithfully as possible at every step.

That is the whole essence of the term "high fidelity", to be as true to the recording as possible.

Absent of tone controls, EQ setting and so on, all components must handle the signal as in the most neutral manner possible, and not impart any change whatsoever in order to be considered high fidelity.

Any DAC or amplifier etc. that audibly has a particular "sound" to it, is by defective by definition.

Why amplifiers sound the same

Reply #14 –
Quote
I think I understand why amplifiers are supposed to sound the same.
They are supposed  to sound the same because the goal of a high fidelity amplifier is simply to amplify the signal...  "A straight wire with gain."

They generally do  sound the same because with modern electronics it's cheap and easy to make an amplifier that's better than human hearing.

Why amplifiers sound the same

Reply #15 –
Rich, just a simple question:

What do you expect from an amplifier? What is your concept of a "normal" amplifier? Do you expect it to have a distinguishable sound? Why? Please explain.
 

Why amplifiers sound the same

Reply #16 –
Quote from: pelmazo on
Quote from: Rich B on
Can you please elaborate a bit on what you mean by "true" sound of the audio? You mention only one way the sound can be true to the original. Do you mean original waveform?


I'm writing within the context of amplifier design, which is the topic you've raised. This perspective treats the input signal to the amplifier as "the original", which is evidently an electrical waveform.

Quote
When you say there is one way for true sound, that the signal must be unaltered on an audible level?


Yes. Signal alterations which have no audible consequences are generally assumed to be irrelevant.

To provide an example for this: Two amplifiers may differ in their bandwidth, i.e. one amplifier has a passband up to 50 kHz, and the other up to 100 kHz. Both limits are significantly above the audible range. Therefore the difference is regarded as irrelevant for their effect on the sound. If they have no other deficiency, both can be true to the original despite their bandwidth difference.


That makes total sense. Thanks.
 
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