I had a Class D amp. I didn't care for it and it ran out of gas early and overheated. To be fair, it was a mass produced Onkyo, and it's probably not the ultimate in Class D design. Right now, I have an A/B amp; the sound is good, but not phenomenal. It is a bit restricted dynamically. It doesn't breathe like a great Class A amp will. But it doesn't really run out of gas and overheat like the Onkyo did. Anyway, those are my thoughts at the moment on Class D and amps in general.
Dave_72 --
Class D amps span many varieties, but I guess I may just share your overall view on Class A amps. I was very happy with my NuForce Stereo 8.5V3 for years, specified at 150 watt with 8 ohm resistance, and through my moderately sensitive speakers (a measured 93dB) and acoustically relatively live 20 square meter listening room never appeared to run out of steam - which, in lieu of the circumstances and different needs put aside, it shouldn't.
Then I got to hear my setup via the pure Class A Belles SA-30 poweramp, specified at 30 watt/8 ohm, and my initial concerns that the sonic imprinting would loose some of its effortless quality at higher volumes with complex music and ditto soundtracks from my Blu-ray collection vaporized immediately; in fact the on-paper less proficient Belles amp, at least watt-wise, turned out to deliver gains in all respects, having never heard my music and Blu-ray collection with as much naturalness and unrestricted, effortless power. The music simply flows unhindered with a simplicity and presence that is very fulfilling - indeed addictive. Here, in comparison, the NuForce appears somewhat congested, rather pale and, in a sense, stifled.
Whether indicative of the true potential and/or possible sonic "signature" of one amplifying principle over the other, it certainly had me revise the need for wattage - in my setup, that is - and also a beginning investment in the Class D segment of amplifiers. It's not that I'm oblivious to other factors that are important when speaking of power delivery (if we're to limit the aspects evaluated, and not go deeper into sound quality per se), not least the "bodily" feel of it, but I guess it just surprised me in above named case.
With much larger and more heavily damped listening rooms, greater listening distances and less sensitive/more problematically driven speakers, one can easily imagine the need for many hundreds of watts where 30 Class A dittos would've come up short, and the need for live-like SPL's could even demand more. Striving for the simpler amp construction/topology however seems desirable though, and thus more sensitive speakers are called for than the general general market can accommodate, despite what looks like an upward swing in general speaker sensitivity.
