The preamp gain pot is not within the feedback loop so turning it down does not affect the ratio of the signal being fed back. The PPIMV is if the speaker signal is fed back into the cathode of the PI (as in most amps that copied Leo Fender's 59 Bassman or Blackface models). This makes all the difference.Smokebreak wrote:Thanks Stephan and Colossal. I understand the concept of NFB, but where I have quoted is where I am confused...in the sense that even if you have a non-mv amp, and you are playing quietly, using say a single preamp gain pot, isn't the signal at the speaker reduced, as well? What makes the ppimv (turned down) have less signal, than if you were playing at the same volume, with no ppimv?Darkbluemurder wrote:. Now if you reduce the signal appearing at the speaker by turning down the PPIMV, less signal is fed back into the circuit.
Cheers Stephan