Amplifier Op-amp Rolling Part 2 [Video]

[amirm]

Follow up video I did on op-amp rolling, covering the latest two tests:

[And subscribe to the channel ]

 

[David A]

Hi Amir, Thank you - as a new comer to audiophile music listening I enjoy your measurement data driven component reviews. Your dispassionate technical analysis and teaching of component measurement science has provided me new understanding & perspective versus more common component "listening perspective" reviews! I listen to digital audio sources (streaming and CD). I am wondering, are there perceptible distinctions above highly measuring noise & distortion measurement thresholds (i.e., 95+ sinad measurements) for amplifiers and DACs, or are these truly inaudible and the comments of "listening perspective" component reviewers like "clinical", "warmth", "sound stage width & depth", "instrument placement" ...... a function of the source recording material, not the component? Are comments such as these about the character of a components sound due to the addition of color or distortion to the audio signal output by the component designer who "voices" the amplifier or DAC? It makes me wonder what paying thousands of dollars buys other than reliability perhaps versus much lower cost well measuring components, or are there audible differences that are not captured by the measurements you make? Thanks for your insight!

 

[SIY]

Are comments such as these about the character of a components sound due to the addition of color or distortion to the audio signal output by the component designer who "voices" the amplifier or DAC?

I'm still looking for a solid example of "voicing" in home audio electronics. Over twenty years now since I started asking and still not a one. Just handwaves and anecdotes. So I think it's safe to give up that belief.

 

[Tranquility Bass]

This dude is totally at odds with you Amir LOL

 

[amirm]

This dude is totally at odds with you Amir LOL

He has an ideal "job." You can say anything you want and there will be a number of people who believe you. No need to prove anything either.

 

[amirm]

Are comments such as these about the character of a components sound due to the addition of color or distortion to the audio signal output by the component designer who "voices" the amplifier or DAC?

There is no mechanism to design any such things in electronics. What there is, is our brain interpreting the limited stereo sound reproduction based on clues it captures. These clues vary from time to time and are subject to imagination, bias, etc. This is why when we blind the listener, all of these characteristics disappear.

What is there is noise, distortion, and frequency response error. Noise is noise. Distortion can hide detail but requires a lot of it. It can also cause brightness due to extra harmonics. Frequency response would be colorations but it is rare in electronics.

 

[solderdude]

He has an ideal "job." You can say anything you want and there will be a number of people who believe you. No need to prove anything either.

and of coarse he gets to use the familiar words like 'tighter bass', better soundstage, smoother presentation, more 3D and whatnot. People all want that and as the guy is clearly sponsored by Sparkos he will say stuff like that and his followers will eat those words and rush to Sparkos to 'upgrade' their cheap amps.
They too (like Danny) will hear the vast improvements because .. well... placebo works like a charm.

The output signal of the amp provably does not change but of course the sound does because ... well ... measurements say nothing about the sound.

The sad part is for every review/video with objective measurements showing actual performance (differences) one can find 10x (or more) YT videos and 'reviews' spouting nonsense and 'this sounds better' stuff.

I would say ... proper info is out there but hard to find and 'dry' ... people want 'better sound' and flashy videos with 'flowery talk' and nonsensical 'semi-technical' explanations confirming what they hope confirms what they think (actually t... know) in their heart to be true.

 

[SylphAudio]

Can the phase of the signals be tested as well when swapping opamps?

 

[DualTriode]

There is no mechanism to design any such things in electronics. What there is, is our brain interpreting the limited stereo sound reproduction based on clues it captures. These clues vary from time to time and are subject to imagination, bias, etc. This is why when we blind the listener, all of these characteristics disappear.

What is there is noise, distortion, and frequency response error. Noise is noise. Distortion can hide detail but requires a lot of it. It can also cause brightness due to extra harmonics. Frequency response would be colorations but it is rare in electronics.

Hello,

I have the impression what you are saying is intentional misinformation.

You have the tools at hand. Set up a single end jFet circuit or a Single End Triode circuit connect it up to your analyzer with your standard dashboard. Adjust the cathode resistor, dial the supply voltage and watch all the flavors of distortion you can create just by varying the voltage and bias resistor value. You can dial the sweet spot where the distortion is at a minimum. Or you can craft the idealized SET stair step distortion signature. What ever you like.

More than a couple of years ago using my AP 2522 analyzer I put a tube similar to a 6DJ8 on a breadboard and dialed the distortion up to several %. Yes an attempt at "voicing". I could easily see it on the analyzer but I could not hear it

See this 12B4A triode stair step. This was a SET headphone amplifier with intended SET "Voicing"



or check out this jFet educational toy

H2 Harmonic Generator

This is Nelson's DIY H2 Harmonic Generator, Version 2. This kit consists of one PCB and two selected J113 JFETs, good for stereo operation. You can read about the project here: H2 Harmonic Generator DIY H2 Harmonic Generator Version 1 DIY H2 Harmonic Generator Version 2 After reading these...

diyaudiostore.com

Thanks DT

 

[Tranquility Bass]

and of coarse he gets to use the familiar words like 'tighter bass', better soundstage, smoother presentation, more 3D and whatnot. People all want that and as the guy is clearly sponsored by Sparkos he will say stuff like that and his followers will eat those words and rush to Sparkos to 'upgrade' their cheap amps.
They too (like Danny) will hear the vast improvements because .. well... placebo works like a charm.

The output signal of the amp provably does not change but of course the sound does because ... well ... measurements say nothing about the sound.

The sad part is for every review/video with objective measurements showing actual performance (differences) one can find 10x (or more) YT videos and 'reviews' spouting nonsense and 'this sounds better' stuff.

I would say ... proper info is out there but hard to find and 'dry' ... people want 'better sound' and flashy videos with 'flowery talk' and nonsensical 'semi-technical' explanations confirming what they hope confirms what they think (actually t... know) in their heart to be true.

And it just happens that the 80 buck discrete opamp is way better than its 50 cent silicon counterpart that measures identically in the same circuit. Funny about that

With all of these massive improvements to soundstage and bass reproduction etc from cables and opamps etc they must be very close to perfection in audio reproduction by now

 

[amirm]

More than a couple of years ago using my AP 2522 analyzer I put a tube similar to a 6DJ8 on a breadboard and dialed the distortion up to several %. Yes an attempt at "voicing". I could easily see it on the analyzer but I could not hear it

See this 12B4A triode stair step. This was a SET headphone amplifier with intended SET "Voicing"

What? That is not "voicing." Simply raising distortion is not voicing. Tuning the frequency response of a speaker is that. Not just screwing up the design to see more distortion. And the fact that you could not hear it, adds to the fact that it is not voicing.

I have the impression what you are saying is intentional misinformation.

Best example of projection I have seen recently....

 

[solderdude]

And it just happens that the 80 buck discrete opamp is way better than its 50 cent silicon counterpart that measures identically in the same circuit. Funny about that

Yep, that's not weird at all.. once you realize that the cheap NE5532 and the 160x more expensive discrete part both have better performance than the output stage (TPA3255) which comes after the op-amps.
So the performance is limited by the TPA3255 output stage and not by the op-amps.

Can the phase of the signals be tested as well when swapping opamps?

The phase of the signal is determined/limited by the output filter of the class-D output stage. That of both op-amps is vastly higher up in the frequency response than that of the output stage to make any impact so its a pointless endeavor.
The op-amps provide buffering and a small amount of amplification which is very easy to do even far above the audible range.

 

[amirm]

Can the phase of the signals be tested as well when swapping opamps?

It can but to what end? Check for stability or something else?

 

[AudioSceptic]

What? That is not "voicing." Simply raising distortion is not voicing. Tuning the frequency response of a speaker is that. Not just screwing up the design to see more distortion. And the fact that you could not hear it, adds to the fact that it is not voicing.


Best example of projection I have seen recently....

I agree, but I can see where the confusion might arise. Is there an agreed definition of attributes like "voicing"? Is it simply FR deviations, or could it also apply to, say, increased bass distortion giving a "thicker" sound?

 

[SIY]

Is there an agreed definition of attributes like "voicing"?

Generally. And that is giving the device a sound that deviates from neutral in a specifically designed manner.

Distortion has to be surprisingly high to be audible. The only time I've encountered that is from a tiny market niche, certain SET amplifiers. And even then, it only manifested at higher volumes where the amp is clearly struggling or from frequency response errors which aren't intrinsic to the amp but a result of the loudspeaker's impedance interacting with a high source impedance.

"Voicing" does NOT happen (or has never been demonstrated to happen) from the choice of capacitors or resistors or wire or whatever, which is usually where these evidence-free claims originate.

 

[Multicore]

Well, I think that settles it.

I'm unsure about where you say "Hopefully we won't have to argue about this." Of course we won't. It is as you said, very very conclusive. No further controversy.

 

[Multicore]

"Voicing" does NOT happen (or has never been demonstrated to happen) from the choice of capacitors or resistors or wire or whatever, which is usually where these evidence-free claims originate.

If "component" means a circuit component, e.g. capacitor, op-amp, etc then yes.

But in David's sentence I understood the word to mean a sub-system of an audio system e.g. power amplifier, phono preamp, etc.

Your dispassionate technical analysis and teaching of component measurement science has provided me new understanding & perspective versus more common component "listening perspective" reviews!

If so then I expect there are examples of, say, power amps that are voiced different from flat.

 

[SIY]

If so then I expect there are examples of, say, power amps that are voiced different from flat.

And yet... I've been asking for decades and not a single demonstrated example beyond source impedance interactions (which are more a function of speaker and NOT consistent for a product) has been named.

Not one.

 

[Multicore]

And yet... I've been asking for decades and not a single demonstrated example beyond source impedance interactions (which are more a function of speaker and NOT consistent for a product) has been named.

Not one.

So you do mean whole amplifier products. Ok. I would have thought there were amps with weak/compressed bass owing to power supply limits or whatnot but I'm just guessing. Let's keep asking!

 

[SIY]

Ok. I would have thought there were amps with weak/compressed bass owing to power supply limits

Run within their power limits, no.