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RE: Audioromy FU29 amp

Yes on the ESL-57's the Audioromy FU29 and the Citation II had a similar sound at moderate levels, but pushed at all and the FU29 quickly became harsh and the bass folded up. The Citation II sounded better at anything beyond moderate (i.e., background) levels. Quad ESL-57 has an efficiency of around 82 dB/ 1 watt, so they want a little power.(I have the Wayne Piquet Zener protection boards in my Quads, so I don't have to worry about arcing them when using 60 watt amplifiers.) The FU-29 did better on more efficient speakers like those Polks, plus there was an euphonius interaction between the Polk and the Audioromy FU-29 that I really liked. Since the Audioromy amp is not an "ultra-linear" design, I suspect there is less overall feedback and so interaction with speaker/crossover impedance will be a little more exaggerated than with ultralinear or other designs that feature a little greater overall feedback. In a sense you're doing speaker / amp matching to act as a kind of "tone control" but it's more than just a changed frequency response curve, in my opinion, that results- there is a change in the character of the sound that goes beyond a simple EQ curve when you pair certain tube amps with certain 2- and 3-way speakers. The tube amps do things with harmonic content - their residual distortion has a character that can "sweeten" the sound in some cases- and with the right amp and speaker you get a frequency response curve and harmonic "treatment" from the tubes that can produce a more "lively" illusion from the recorded music. Is it more "accurate?" No, probably not. Does it sound good to listen to? Yes, it certainly can sound very nice, and with certain tube gear/speaker pairings this "good coloration" also produces sound that is very non-fatiguing, something which, paradoxically, the more "accurate" gear sometimes fails to do.

Typically, I use a Soderburg-modded Forte 4a on the Quads. But sometimes I want the Citation. The solid state, class A Forte amp has better bass and yet sounds quite "tubelike" in the mids and treble- except it's treble is more extended. The Citation has a slightly more laid-back treble and 'rounder' bass which I also like sometimes. I have a switch arrangement so I can select which of the two amps suits my preference at the moment.

I also have an AMC CVT-2030 which is a class-A hybrid amp with MOSFET drivers and EL-34 output stage. I think this is a very under-appreciated amp, it sounds really wonderful on the Quads, but it lacks just that little bit of extra power I want at times, which I can get from the Citation.

I have also tried the AMC CVT-2100a which again is a class-A hybrid amp, this time using MOSFET drivers into KT-88's. It was OK, had good power, but somehow it was not as satisfying as the Citation II. It was not just a higher-power version of the CVT-2030 sound, it didn't have the same 'liquid mids' as the EL-34's in the CVT-2030.
Science doesn't care what you believe.



Edits: 03/26/11 03/26/11 03/26/11

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