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Negative feedback Amp=more faithful reproduction?

Negative feedback (NFB) vs zero negative feedback (ZNFB). There seems to be unsubstantiated contention that ZNFB amps sound more realistic. I know this is an age old debate favoring the ZNFB design, but I think most audiophiles have never bothered to look into this matter and believe the advertisements and proponents of zero NFB design. I have been in that camp until recently. My own experience and research into articles on this matter leads to me believe NFB is needed for faithful reproduction of music. I'm not saying NFB design is more "musical", which is a highly subjective term and usually means more euphonic or colored. I've posted a similar question awhile back, but I was hoping we can have a more evidence based discussion on this matter. Perhaps, we need clarification of descriptive terms we use to describe sound. My contention is, in general, NFB designs produces a more accurate or faithful reproduction of music than ZNFB designs. Here is a very good article on feedback and distortion:

http://sound.westhost.com/articles/distortion+fb.htm
dracule1
dracule1 OP
1,043 posts
 
Hi Kijanki, thanks for your input. What do you think about the article I linked?
dracule1 OP
1,043 posts
 
Hi Elizabeth, what is a current fad or "catchphrase" is not important to me, but the finding the underlying reason for "catchphrase" or current fad is. If I did't think NFB or ZNFB made a difference in sound, I wouldn't have made this inquiry.
dracule1 OP
1,043 posts
 
Elizabeth, I have and owned amps that have adjustable NFB, and you can clearly hear a difference between different levels of feedback. IME, the higher feedback setting produced more realistic sound. So your contention feedback has little to do with how a product sounds is in direct contradiction to my experience. Do you have any amps with adjustable feedback? If you do, I would be surprised if you can't hear a difference.
edwyun
196 posts
 
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.
mt10425
1,138 posts
 
Adjustable NFB is a great way to prove individual preference, not a technical absolute. You used the phrase 'more realistic sound'. To you. We're engaged (yet again) in a thread of trying to prove others to be less knowledgable, savvy and just downright wrong in their audio beliefs compared to the OP. Why? It's great you've seen the light. Is validation that important to you?
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