Aragon 4004 mk2 vs Adcom 555 mk2

Hmmm, Im gonna have to start a new thread on feedback. 0 feedback designs, and if 0 feedback is necessary onlly in the source if using xlr's or the opposite etc.

Gmood1...Negative feedback just means that the amp output is compared with the input, with appropriate gain and phase compensation, and the resulting "error signal" is applied to the input (or at some intermediate stage) so as to reduce the error signal to zero (nearly). There is no fundamental reason why negative feedback is bad, but if an amp requires too much this probably means that the circuit is not too hot to begin with.

Tube amplifiers that use transformers must have negative feedback to get flat frequency response, quite apart from the issue of distortion. The widely used "ultralinear" configuration has taps on the output transformer specifically for the purpose of negative feedback.

Thanks Edartford for the info.The Music Reference has 3 settings for feedback and the manual stated for best results to leave it on the lowest setting.It was very easy to hear the differences when changing from one setting to another.The more feedback the more the soundstage seemed to get clouded up.

I have used amps with feedback switches too (like the Unison Simply 2 and 4 tube integrateds) and I didn't find the soundstage "clouds" up really when i go to high feedback. I would say that it is more of softer and slower sound instead but I could hear the same background details in both with no difference in level. It was more of a mood change IMO. I about wore the switch out going back and forth and came to the conclusion that the difference was overall quite subtle. My brother couldn't hear the difference in a blind test but I could albeit just barely. I think the switch went between 6 dB and 12 dB. Pretty cool - I would like to find other amps with a toggle switch like that and listen again. ciao - Arthur

Aball thats what I was trying to say in other words.It does seem a tad slower and softer.Which to my ears is slighlty cloudy.I really don't understand the reason for having these settings.When the designer states for the most transparency leave it on the lowest settings.Then again maybe it has something to do with matching the preamp or cd player gain to the amplifier.I don't know ..Aball your the engineer how about shed some light on this.