Solid state design options...

Bombaywalla, great post. Please do not assume I have bought into the "all negative feedback is bad" camp, as that is not the case. I merely mentioned VAC's site as interesting food for thought, and much of what they have to say is probably applicable primarily to tube amps due to the presence of the output transformer. I will say, however, that two of my favorite amp designs presently are Pass X and Ayre V_x, both of which are touted as "no feedback" designs, and both of which sound purer than most anything else out there. And I would venture a guess that both of them have quite high DF to boot.

Karls,

Thanks!
OK! Sorry to club you with the "all negative feedback is bad" group. Your post seemed to indicate that but it seems that I misinterpreted it.

Very interesting and well put, Bombay! (The EE in you manifested himself, thankfully:))

Engineering a constant current device is a bit tricky, (albeit nice for speakers) especially when we go over the sacrosant 2,83V level. Astonishingly, it seems that some SS amps have been designed with the full throttle in mind, linearity falling as we lower the volume.

For that matter, how many of us nowadays listen at more than ~4V at the amp output -- with a 89-90db efficiency speaker that's enough to tire the ear pretty fast!

The reason I ask is because some have very stong feelings on this subject. For example, Richard Hardesty (Audio Perfectionist Journal) consistantly claims that the best sounding amps that he has heard are fully-balanced in design w/ no global feedback. However, he doesn't really talk about any other factors of amp design (at least, not yet).

Other reviewers have ranked amps of *very* dissimiar design very closely together. A Clayton M-100 is very different from a McCormack DNA-500, but I have seen them referred to as comparable. Throw tube amps into the equasion, and on paper, things get confusing really quickly. However, the confusion is usually quickly sorted out *if* you are able to do side-by-side listening comparisons (which is generally logistically difficult to do).

Oh...and I apologize for my spelling of 'architecture' in the original post.

Nrenter,

Understand why you posed the question in the 1st place. I agree that it's very hard to discern an amp's sound quality by just looking at the specs & knowing what sort of technology was used to design it. I also agree that the best is to listen to it.

You know, we might be surprised when we open up the M-100 & DNA-500 & place them side-side! It is quite possible that the 2 independent designers used techniques more similar than dis-similar to design their resp. amps! Neither designer provides much info about the techniques used & we have to rely on the IAR journal to ferret these out for us. I suppose that you are referring to that IAR80 article, which I also read with a lot of attention, that put both these amps in the same class.

We just don't know what these designers are putting into their amps esp. if they as tight-lipped as Wilson Shen & Steve McCormack. I read a review on the M-100 amps, which was a reprint of a Bound For Sound review, where I was informed that I should not use high impedance 10-16 Ohm speakers nor should I use a tube pre with the M-100 if I really wanted the amp to sing. J. Peter Moncrieff never mentioned this in his article! So, should I/we append this tit-bit of knowledge on the M-100 to the knowledge gained from the IAR80 article? Don't know......