SET amp w/Neg feedback?

I prefer less feedback. I've owned amps that had adjustable feedback and they always sounded more musical with zero feedback.

This assumes that you have a reasonable power match between your amp and your speakers. If you don't, then a little feedback may sound like it provides greater control, but it will come at the expense of transparency, harmonics and tone. I prefer to correct the amp and speaker mismatch before I compensate by adding feedback.

In systems where big punch and power are desired more than sublety, I've heard push pull amps that I liked using up to about 6db of feedback. Any more than about 6db of feedback in any amp dampens harmonics and transparency too much for me. An example of an amp using about that much feedback that is very musical is the Tom Evans Linear A. Still, when compared to an excellent zero feedback amp, one gives up some harmonics, decay and transparency.

In short, I don't think an SET amp with more than 5db feedback is a "good thing" and I believe less is better.

Where I termed it "big punch and power" I think Ralph is calling it "sound **pressure**" and I believe his term is more precise. If that is the goal, I'm skeptical that a marginal addition or subtraction of negative feedback will have significant sonic benefit or detriment.

I do believe that when using a properly matched speaker and tube amp combination, that marginal reductions in feedback yield significant sonic improvements. If your goal is to hear the harmonic tones of a violin, be able to pick out the timpani skin from within Solti's 9th symphony, hear how Neil Young's rythm guitarist scrapes the side of the pick along the length of a string or hear the unique tone of Hendrix's marshall amp at any volume, then less feedback is better. Jeff