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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
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edwyun
244 posts
 
"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.
roscoeiii's avatar
roscoeiii
1,155 posts
 
I am by no means a technical expert and have enjoyed both NFB amps and ZNFB designs, but I did want to note the perhaps it is a good idea to bring the human brain into this conversation (I am a neuroscientist, so I can't resist). Namely, it is fine that we are able to measure amps on the bench, but we also need to acknowledge that our ultimate enjoyment of an amp-speaker combo is based on how our brains process the signals that reach our ears. Psychoacoustics plays a major role that can't be overlooked, such as determining what frequencies we can hear most acutely and which order of distortion is more noticeable.

Also lurking in each individual brain are personal preferences. Nelson Pass' First Watt line of amps is a great example of a wide variety of design choices that are intended to both give a good match with certain types of speakers and to provide different flavors to account for different listener preferences.
lloydc's avatar
lloydc
751 posts
 
it's adjustable on my amp (Mesa Baron,) so it is easy to hear the differences. I have ears, so I do not really care about the technical rationale. Some music sounds better with a little NFB (primarily studio produced rock), but most music sounds better without any NFB, at least with my system. In general, the sound is a bit less "alive" with NFB, but if a record is made with lots of compression, that hardly matters, and other factors come into play.
charles1dad's avatar
charles1dad
10,250 posts
 
I 'm glad to see most of the replies are based on common sense and actual listening experiences.Which ever amplifier type sounds best to you, that's the one to buy. No need to cite this paper or that article to strengthen your preferences. I don't know why people need validation for their choices. For me, I'll take a well designed ZNFB SET amplifier anytime.It matters none at all if someone prefers something completely different, so what.Make a choice and stop worrying if others disagree. Different ears (and brains)will choose accordingly, imagine that.
Regards,
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