Voicing an amplifier: general discussion

[M Gregg]

Ok so in a nut shell,

All amplifiers sound the same unless there is a gross distortion in one of them.

There you go no more problems.
The list:

All SS amps,
All tube/valve amps even if wired in triode/pentode or UL
Class D and everything else in between.

Job done. 😀

Then we can go on to say no components used in them makes them discernible from each other no output topology PP or SE etc. The type of transformer used PSU caps used or anything linked to support structures or damping. If you can its distorted or lacking in some area.

Well that was quite easy.
The court is now out of session, save your money and buy a better car!
Or some beer.
If you buy something esoteric its either keeping up with the next door neighbour or outdoing your mates.
Great I can forget this now..🙂
NB remember this includes output Tx's and coupling transformers as well.
If you can hear a difference you are imagining it, because in blind testing you will not be able to tell the difference.
There must be a lot of distorted amps out there..better off with a MIDFI its cheaper.

Regards
M. Gregg

 

[M Gregg]

From a theoretical perspective,

Its correct..no amps sound any different unless some distortion is evident.
WHAT A STUPID COMMENT!

Its like saying unless you are at the venue listening to the sound its distorted.
You cant tell one amp from another in blind testing well they must all have the same level of distortion then.

The point would be that all amps are flat within the level of perceiving distortion.
IE you are listening to a recording..if the sound is only that of the recording and nothing else then I agree you won't hear any difference.
If the human ear cannot detect the difference in topology of a circuit there is no point in going any further..design is pointless.
The only gain from design after this would be to make it cheaper to build or lower running cost.

Regards
M. Gregg

 

[jan.didden]

Then show me the MEASURABLE DIFFERENCES that all power amps have.

That is possible, but not always with a simple THD figure. Problem is that for advertising and general publicity you really need a simple number that anyone can understand and THD is perfect for that.

Multitone testing and testing with realistic speaker models instead of a fixed load resistor, just to name a few, go a long way to show measureable differences between amplifiers. If I'm not mistaken, your SR1 has multitone testing features, possibly even DIM30 or DIM100.
It may be an interesting experiment to put your poweramps through such a regime. Realistic speaker load circuits can be found online.
Of course that still leaves the issue of how audible these differences are.

Jan

 

[M Gregg]

This is interesting,

The arguments on building HIFI...any argument about a circuit design or feedback is again pointless. If the level of distortion is below what the human ear can detect there is no argument..

If you put the two engineers or diyers amps in a blind test you should not be able to tell the difference..
if you can't then there is no relevant argument..
if you can one or both are distorted.

IF ALL AMPLIFIERS SOUND THE SAME IE THEY ARE BUILT TO ONLY REPRODUCE EXACTLY WHAT THE SOURCE PUTS OUT.
The arguments are about distortion.
However if this is not detectable by blind testing..there is no argument it is purely academic.

Its a bit of a slap in the face if you spend $10,000 on either building an amp or buying an amp and it can't beat a MIDFI pioneer.
IE it sounds the same in a blind test.

There is always more..
Any modification to an amp DIY or other, if it alters distortion lower... when the original amps distortion... was lower than the human ear can detect.
It should not be possible to hear it..if you can you must have added distortion that is now in the hearing spectrum.

If blind testing is correct!

Regards
M. Gregg

 

[M Gregg]

So final comment.

If an amplifier is in a blind test and its distortion is below hearing..

I have connected this amp in triode and it sounds better.

I have put LED's in the cathode..

I have changed the power supply or caps..or coupling caps..or dc coupled etc.

I have changed a tube or tube type..

I have changed a heat sink..or type of transistor.

I have used this chip amp and its better than the other one..

The only way this would be true is all the above are working in the hearing range (for distortion)or your just kidding yourself.
You are designing for distortion type or level unless its outside of being detectable in a blind test!

So is the blind test flawed, or are we just hearing things that don't exist, or are all the amps distorted into the hearing range (they are all effects boxes to some degree)?
Put them in a blind test and the MIDFI pioneer is the same or better?

Regards
M. Gregg

 

[cegadede]

So is the blind test flawed, or are we just hearing things that don't exist, or are all the amps distorted into the hearing range (they are all effects boxes to some degree)?

Regards
M. Gregg

If we are taking about competent amps running below clipping, you're just hearing things that doesn't exist.
That happens a lot ( ie, look in youtube for a video on the mcgurk effect).

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[vacuphile]

OK, you're talking about acoustic measurements. I was questioning the claim that electrical measurements are more easily performed on an amplifier. Why is it harder to stick your voltmeter or scope leads on a speaker's terminals than an amplifier's innards?

Sorry Nezbleu, I have to frankly admit that I have not in great detail followed this thread and that I reacted to your post out of context. The following might be out of context all over again.

As far as electrical measurements are concerned, it can be argued that it is harder to measure a speaker than it is to measure an amplifier, but also that it is quite useless.

It is harder because in measuring the electrical speaker behaviour, you need to define current + phase of current per frequency, assuming that the voltage is fixed by the amplifier. What these measurements will give you is a soup of data that might look really horrible if you think they are correlated to the sound that is being produced. However, this relationship is indirect.

For example, most speakers show a decrease in current around their xover frequency.You might conclude that this is a bad thing, since less energy is flowing into the loudspeaker. However, this is not bad at all. Because, in the xover region, two drivers are functioning as coincident drivers, giving a 3dB efficiency boost. If you were to design the xover so that the total energy flowing into the speaker would be constant, this would result in a peak.

In other words, it is the acoustical output that counts, and electrical measurements can't tell you much about this. The only reason to do electrical measurements on speakers is to see what kind of load they will present to the amplifier. But, since I am reacting out of context, this is most likely what you where arguing in the first place.

Congrats with your talented daughter.

 

[M Gregg]

If we are taking about competent amps running below clipping, you're just hearing things that doesn't exist.
That happens a lot ( ie, look in youtube for a video on the mcgurk effect).

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https://www.youtube.com/watch?v=G-lN8vWm3m0

so audio has been complete rubbish since 1955..or is it visual distortion.

Regards
M. Gregg

 

[cegadede]

https://www.youtube.com/watch?v=G-lN8vWm3m0

so audio has been complete rubbish since 1955..or is it visual distortion.

Regards
M. Gregg

Yes, that's the video I was talking about!

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[M Gregg]

Yes, that's the video I was talking about!

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So how much in audio books is real? ie it makes an audible difference

I'm talking text books of topologies and best build practice.

Are we saying that after a point its all rubbish..I think the quote was 2% THD.
In a blind test non of it is relevant?

IE this component sounds like BA BA..and this components I think sounds like FA FA..same for topologies or modifications? below 2% THD.
The ear can't hear a difference but the brain says there should be because it looks different so it creates the illusion that it is different?

You can measure a difference but its complete rubbish in a blind test below 2% THD.
Which would make all measurements below this level of no impact at all..all the engineering banter tests changes mods has no impact?
That would appear to be what the blind test is saying all the scope tests and anything else to create a better measurement.
We see the scope trace with improved distortion but we can't hear it so the brain makes it sound different?

So speakers would be better behind a curtain as well or wear glasses that stop any vision..so you can only hear the difference..not see it..
It would be interesting can a blind person tell the difference between amps? ie in the TEST!

JUST LOOKING AT THE OTHER SIDE OF THE ARGUMENT!

Buy a second hand reasonable amp and forget everything else..😀
Just thinking about our concept of reality..

Regards
M. Gregg

 

[DrDyna]

Yes, that's the video I was talking about!

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Pretty cool video. Might explain why eliminating the eyes as a variable is absolutely necessary to properly test a device which is only supposed to stimulate the ears, and why people keep insisting that they hear things that they don't because they've been allowing their eyes to confuse their ears for so many years.

 

[jan.didden]

Just thinking about our concept of reality..

Regards
M. Gregg

Fascinating journey you are on! You my friend are one of the few people here who really think about the concepts and their beliefs and the implications.
I respect that, and yes I am serious!
I did a similar journey many years ago (not audio though). Really changed my outlook on the subject.
You must have read my sig line 😉

Jan

 

[auplater]

Discovery channel stuff

Not at all. I've heard the same argumentbefore. I'm not missing it, it simply does not apply.


If you read back into the thread, you will see that the scorn came quickly from those opposed to the original topic. Like so many threads on audio forums, the immediate reaction is "Holier than Tho". Not help, not teaching.

My plea is for a technical discussion of what real, measurable amplifier parameters can lead to subjective differences. A sort of cross index, if you will.

Sometimes the truth hurts... all I see is continued efforts to deny. and shout down any attempts at rational discussion and contrary views.

Reminds me of the supernatural researchers on the boob tube chasing Moth man, Sasquatch, haunted mansions, alien abduction, Roswell events,, etc. with all manner of technical gear, looking for electromagnetic events, radiation signatures, etc. to somehow prove their reality using psuedoscientific misdirection.

Plays to the crowd in a Big way, and I suppose sells lots of advertising, but has zero relevance to reality, other than filling airtime.

Since subjective differences are by definition observer specific, I find this request for some sort of technical cross reference ironic at best, and most likely oxymoronic. Looks like a feeble attempt to legitimize user preference as a technically observable dogma, IMO

John L

 

[JMFahey]

If the human ear cannot detect the difference in topology of a circuit there is no point in going any further..

If you restrict yourself to improving audible differences, yes.

design is pointless.

Don´t get depressed, there´s many other amp design areas in which advance is not submicroscopic.

The only gain from design after this would be to make it cheaper to build or lower running cost.

Once you reach the point of diminishing returns, which we have reached quality wise, you have to focus on something else.

The only exception is people who call themselves "Audiophiles", who consider themselves gifted well beyond mere mortals, who think they

detect the difference in topology of a circuit

just by hearing in a blind test (I´d LOVE to see that 😉 ) and who feed a Faith driven specialty market which is about 0.0001% of World Audio market.

And I´m probably being generous.

 

[cegadede]

If you restrict yourself to improving audible differences, yes.


Don´t get depressed, there´s many other amp design areas in which advance is not submicroscopic.


Once you reach the point of diminishing returns, which we have reached quality wise, you have to focus on something else.

The only exception is people who call themselves "Audiophiles", who consider themselves gifted well beyond mere mortals, who think they just by hearing in a blind test (I´d LOVE to see that 😉 ) and who feed a Faith driven specialty market which is about 0.0001% of World Audio market.

And I´m probably being generous.

+1

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[TonyTecson]

Since subjective differences are by definition observer specific, I find this request for some sort of technical cross reference ironic at best, and most likely oxymoronic. Looks like a feeble attempt to legitimize user preference as a technically observable dogma, IMO

this sums up what this thread and many other threads like this before are all about...

 

[DrDyna]

...who think they just by hearing in a blind test (I´d LOVE to see that 😉 )

Quite a few people would love to see that, one has even offered a large cash prize if anyone can, but the prize remains unclaimed, despite hundreds of tries and the excruciating roar of grumpy audiophiles who think science doesn't apply to hearing.

 

[SY]

mmm, yes he did. How did you interpret a various list of amps all sounding the same?

He didn't even say THAT. What he said was that he couldn't distinguish among this particular group of amplifiers with his ears and his speakers. Not surprising since all of these these amps are all stable, have flat frequency response, low output impedance, no gross distortion, no gross noise, and good stability. He also said that he would be able to hear differences with power if he used inefficient speakers or speakers with bizarre input impedances.

This is totally unremarkable. There is a lot of experimental data showing which amplifier parameters people CAN hear, and those are level, frequency response, noise, stability, clipping, and gross distortion. This small group of amps all are fine with those parameters. No-one has EVER provided any evidence that there are other important amplification factors. Much assertion, yes, much anecdote, yes, but no actual evidence of greater quality than claims of fairies in the garden (as DF96 puts it) or alien abductions with anal probing (as I put it).

This is why what you are actually looking for is a tone control which will cause exactly the sort of audible changes you're after. You can set it flat for excellent recordings, tilted downward for recordings that need to sound warmer and sweeter, tilt it up for recordings that are dull. An EQ is even better, but more inconvenient to reset from recording to recording.

 

[yldouright]

auplater
Welcome.

DrDyna states: Pretty cool video.

...and then uses the McGurk effect video to buttress the argument for AB/X testing. Looked at another way, the video also confirms the remarkable ability of the brain to wipe away real differences and distill them to parity. See page 3 for an example. Psycho-acoustic effects are not unidirectional.

 

[yldouright]

The narrow set of audible parameters in SY's post do not include soundstage (imaging) so what of it? Does everyone agree each amp that is fine produces an identical one or that it is not an audible characteristic?