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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
picfink
8 posts
 
Ed:
Pass does indeed up simpler circuits. His XA.5 and X.5 series apparently have but 2 gain stages. So, in that case would feedback be 'global' or 'local'?
Also, Pass amps I see the specs for are about 26db gain...which is on the low side for people accustomed to 30db PLUS gain.

If I could afford it, I'd get Pass amps for my panels....I see a pair of XA30.5s at Reno which would be perfect for a biamp setup! (another can of worms)

Other posts address feedback without ever defining if they are speaking to Global or Local. It makes a big difference...
kijanki's avatar
kijanki
3,575 posts
 
Edwyun, this particular design (Icepower) uses Nielsen Karsten multiple feedback. One feedback comes from modulator while the other is from the speaker output. Class D is relatively linear to start with, while output impedance is inherently low hence it doesn't require a lot of feedback. In addition it is only one stage (modulator) making for small signal delay - less chances of TIM. Early class D consisted of primitive sawtooth modulator while this resembles sigma-delta A/D converter's modulator. There is nothing wrong with class D (SACD,DSD are class D) but carrier frequencies are still too low (Mosfets are getting faster every year). For the money it is bargain IMHO.
kijanki's avatar
kijanki
3,575 posts
 
Sorry for double post
edwyun
196 posts
 
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 OP
1,043 posts
 
Kinjanki, I think the Hyperion 938 is truly one of the great speakers in high end. I regret selling them to a friend. You can get 938s at bargain prices now. I am thinking of getting another pair.
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