Negative feedback Amp=more faithful reproduction?

The reference to Class D amps is interesting. Generally, they use a form of negative feedback for pulse width modulation type of amplification.

IMHO, NFB and ZNFB are different tools (among many, many others) that an amplifier designer has at his/her disposal to get the best performance (or let's say, for our discussion, the best faithful reproduction) given the amp's design parameters.

Some amps are designed to work better with NFB while other amps are designed to work better with ZNFB. So I don't think anyone can categorically say one method is better than the other for faithful reproduction, whatever that means.

Having said that, I personally prefer amps with the simplest circuit designs because I subjectively believe (rightly or wrongly) that the less capacitors (not power supply caps!), resistors, boards, etc., in the signal path means there is potentially less chance that there is going to be any change to the signal from input and output at the amp. That, to me, means ZNFB. But that also means that the amp design has to be inherently linear so that it doesn't need NFB to begin with.

I tend to prefer Nelson Pass designed amps - from Thresholds, Pass Labs, and First Watt. Almost all are ZFB designs. However, even Nelson Pass uses NFB in some of his amp designs because it works for that particular amp.

So, if you like a particular amp that was designed with NFB or with ZNFB, and it sounds good to you, then listen and enjoy it.

"Curious, Have you ever listened to SET amps (hopefully with the proper speaker)?"

Onemug, I have listened to some SET amps and OTL amps, all operating in Class A (oh no, another amp design principle!). In my setup at the time, I didn't feel they had the overall extension at both extremes or bass slam I like. Perhaps I should have tried more expenses tube amps. =) But they were very good in the midrange and presence. I have since gone to a bi-amp system and eventually may use some SETs or OTLs amps for their benefits in the M/H frequencies (currently using Aleph 2s, which do have some SET characteristics)) and use SS amps for their bass slam in the L frequencies. It's all a balancing act.

"NF design is just one aspect. Alone, it means relatively little."

And I would go so far as to say design elements other than NFB (or ZNFB) have a greater effect on how an amp sounds.

Take it all in perspective. Enjoy and happy listening!

Dracule1:
So you are looking for a technical explanation as to why you like and find more realistic your amp with NFB than with ZNFB?

I believe the technical explanation is in the article you provided a link to in your OP. Some may agree, others may disagree. I have read that article and others from the author. Some things I agree with and others I do not. He also states that there has been great disagreement on the issue. So why would you expect anything less?

If you agree with the article then fine. That's all there is to it.

Well then it appears that your particular amp needed NFB to begin with.

KJ:
Never said that anything is wrong with Class D. My powered sub is a Class D amp. I mentioned that it is interesting because it has a different way of using NFB.

PC:
I will defer to Papa...

https://passlabs.com/articles/audio-distortion-and-feedback

Dracule1:

You did read this in the article, right?

"Only by testing, working with the devices and taking careful measurements will you find out what really happens. Relying on maths formulae (regurgitated ad nauseam) or 'common wisdom' is not always the best way to get to the truth."

So what did the author use to test his theories?

"For the majority of the tests described, the effects were simulated rather than measured. There are some very good reasons for this, with the primary reason being that the simulator has access to 'ideal' amplifiers. These have infinite bandwidth, infinite input impedance, zero distortion and zero output impedance. Being perfect, they also contribute zero noise."

I know of no amplifier that has infinite bandwidth, infinite input impedance, zero distortion, zero output impedance, and contributes zero noise. If anyone has one, let me know, I would like to purchase it.

Also, you did read his qualifications, right?

"PROPERLY IMPLEMENTED, negative feedback will invariably reduce distortion to levels that are well below audibility. Not just harmonic distortion, but the much more intrusive intermodulation distortion. IF DONE INCORRECTLY the results can be awful."

I agree with this statement. But therein lies the rub. And you do realize that in the 70's NFB was used to get distortion below audibility. But most agree that, as implemented, it sounded pretty bad.

KiJani:

I think you're talking about distinctions between local feedback and global feedback.

Mapman:
The answer to your question is to do away with reproduction altogether. Sell all your equipment and go to stadiums, concert halls, jazz clubs, auditoriums, amphitheaters, subways, bathrooms, etc. Go live!

Mapman:
Distortion is good, so long as there is not too much of it!