Who tried Class D only to return to S/S or Tube

As has already been stated, the pre-amplifier is as important to the sound of class D. One cannot simply swap out an AB amp for a D. The system must be coherent and matched. I'm fine with my Bel Canto and Wyred monos driven by Modwright tubed pre-amplifier.

My Rowland 102 sounded the best after about 400 hours. Class D amps are very revealing and often don't work well with some "bright" components. I cannot say if class D works better when powered for a while since it is always on in my system. It doesn't even have on/off switch. Yes, trebles are different, more natural IMHO. Cymbals sound fuller and brassy and not "splashy" as it was with class AB amp. It requires some time getting used to. Midrange is just wonderful.

Hi Jeffb28451, which Rowland class D amp did you listen to?

G.

11-28-15: Kijanki
My Rowland 102 sounded the best after about 400 hours. Class D amps are very revealing and often don't work well with some "bright" components. [...]

The exposure goes both ways; what's at the end of the signal chain (i.e.: speakers) can also be ruthlessly revealing as well as, conversely, reveal their limitations. When people describe SET's as possessing "lush, warm [i.e.: meant as warmer than strictly "neutral"] midrange" and generally "loose bass," it could be descriptive of speakers lacking mids resolution/speed and of (bass-)ported designs with poor damping and overhang. Connect well-implemented horn speakers instead (themselves far more revealing than most direct radiating designs) with non-ported bass of higher damping and the "math" can suddenly reverse into match-bliss: here the mids are no longer warmish warm, but attain a "bloom" and naturalness that's ultimately freeing of any containment resembling "hifi" in the usual sense, and a bass enriched with an organic imprinting more about texture, immersion and cohesion (traits of true horn bass as well) than oomph, attention-seeking and depth.

If one were to insert a Class-D amp here instead (many iterations though they are), and the sound suddenly became slightly bleached, bass-thin and lacking fullness (that's a guess), my take would be to assess the amp lacking harmonic richness and being over-damped in this particular setup rather than aiming the search light towards other components - not least the speakers. Though speakers (and their acoustic environment) are by far the most coloring and limiting factors, their potential to put into perspective on what to use earlier in the chain is significant.

One cannot simply swap out an AB amp for a D. The system must be coherent and matched.

This seems to be in response to my post so I will bite...and ask what do you mean by "coherent and matched?"

I didn't mention that I tried the amps with three different preamp options, two of which were made specifically for the amplifiers, by the same manufacturer that made the amplifiers. Because two of the preamps have low impedance outputs, those two matched well with either amplifier wrt impedance. The highest gain preamp was +6dB and the other two have zero gain, while the source is 4V. These numbers work well with either of the two amplifiers. Are there other parameters that need matched? Regarding coherence, what attribute or parameter would make one preamp more "coherent" than another when used with a Class AB or Class D amp, and couldn't the same preamp be "matched and coherent" with both of those amplifiers?