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 1 response by audio_ken

If a person cares to look in any book covering filter theory, they'll find gain/phase graphs that illustrate propagation or group delay. For lowpass filters, which is what most amplifers are classified as, low frequencies have little or even no delay while higher frequencies have more, such as the nominal 45 degree phase lag at the -3db point. A phase lag corresponds to a delay.