SET amp w/Neg feedback?

Rockadanny, it all has to do with the intention of the designer. In general, if the designer uses tubes its probably a Power Paradigm speaker he created. Voltage Paradigm designers usually use transistors. That will answer the question about 95% of the time. Beyond that, its a good idea to talk to the designer and/or read any white papers he may have written, or simply ask what sort of amplifier he recommends.

The equipment matching conversation that is all over high end audio is a direct result of the conflict of these two paradigms.

Ralph;is there a speaker that performs well in your opinion that operates within both of paradigms you mentioned;just wanted to hear your view on those types of speakers.

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.

Rleff, the key to that is a flat impedance curve. The Avalon Eidelon does that well, as well as most magnetic planars, whose impedance curve has nothing to do with box resonance :)

There is another issue- the difference in performance between low impedance speakers and high impedance. Actually, the difference in impedance has little to do with the speakers and everything to do with the amps: **all amplifiers** regardless of the technology, will sound better driving higher impedances. IOW if sound quality is your goal, it will be better served by an 8 or 16 ohm speaker as opposed to 4 ohms, all other things being equal.

Another way to put this is if you had a speaker with 2 woofers, 2 midrange units and 2 tweeters, and all the drivers were 8 ohms, it would sound better wired as a 16 ohm load than it would wired as a 4 ohm load, regardless of the type of amplifier involved.

OTOH if sound **pressure** is your goal, and you have a transistor amplifier, a 4-ohm speaker might be preferred.

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