2. amps-preamps
  3. 1276402330

What is wrong with negative feedback?

I am not talking about the kind you get as a flaky seller, but as used in amplifier design. It just seems to me that a lot of amp designs advertise "zero negative feedback" as a selling point.

As I understand, NFB is a loop taken from the amplifier output and fed back into the input to keep the amp stable. This sounds like it should be a good thing. So what are the negative trade-offs involved, if any?
solman989

Showing 4 responses by ngjockey

ngjockey
1,042 posts
 
There's open loop (global) and closed loop (local). Few designs can be stable into low impedance loads without some feedback and, if you read carefully, some advertise "no global feedback" and sometimes forget a word. In the case of op-amps, it's usually already there.

Easy to find all the negative things about negative feedback. I'm still waiting for someone to advertise positive feedback as being better :)
ngjockey
1,042 posts
 
Like this?

http://www.wolcottaudio.com/WA_presence.htm

Appreciate Wolcott's integrity.
ngjockey
1,042 posts
 
Best thread EVER.
ngjockey
1,042 posts
 
Ralph, this is the wrong place to ask, but would you care to answer the math as proposed by:

http://www.transcendentsound.com/amplifier_output_impedance.htm

Just trying to get a grasp on the "how". The other controversial article is not related to this thread.

Fascinating relating electronics to chaos theory. Maybe we can use it to predict long term digital format forecasts.
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