what gives? why is rotels new lineup of amplifiers class d? is this the future of amplification? were their class a/b amps not doing well? Is class D amplification done right inferior/superior to a/b amps? Is it just a size/efficiency thing or is their an actual audible/economical difference? Too many questions not enough answers.
Class D is more efficient pound for pound. It also puts off less heat. Some people think it sounds thin/clinical/whatever, and don't like it. Some think it is the next coming of the messiah. Try it and see what you think.
Class D is far more efficient than A/B. Whereas class B is about 65% efficient, class D is about 90% efficient. So class D amps run cooler than A/B, which means that no heatsinks (or very small ones) are required in smaller casework with very little ventilation. You can make a small powerful amplifier that can fit in many environmentally inhospitable locations such as inside speakers, walls, ceilings.
Sonically, class D lags behind A or B, but imaginative solutions (such as Tripath's 'class T' which is class D reworked) have wrought some quality from these amps.
jeff, remember the biggest hype about class 'D'?. It was going to be a chip driven marvel that anyone could afford, offering the quality of an expensive analog amplifier. I have yet to hear quality(yet to hear the Rotel, too!), and sure as hell yet to hear quality at a cheap price that should accompany the technology.
if not class D, something else will come along eventually that will be more efficient and sound great that will become the "standard" (mainstream) of audio that a/b has become for the meantime. A/B your days are numbered!!!
There is no doubt in my mind that class D has potential. I have heard a couple of implementations which have been really quite surprisingly good. The Naim n-Vi is an all-in-one HTIB solution using 5 Tripath (aka class T) amps. As I said earlier, the class T is a reworking of class D. Naim's solution is one of the most musically satisfying. It's not as good as Naim's own class B amps (even the most basic Nait5i), but in comparison to other similarly priced solutions (e.g. Arcam DV137/AVR350), it is at least in the same ballpark and, some would say, even better musically. In terms of clarity, transient response etc., it competes strongly, and this from a one-box solution!
I've also heard the Chapter Audio class D implementations, and although they have left me cold, they are no doubt very capable and compete strongly in their price range against conventional competition. There was no area where they could be faulted, merely not my taste. That said, Chapter have had a couple of implementations and there's no doubt in my mind that the latest are most definitely leagues ahead of their first implementation.
I think the designers are learning how to make the technology work to best effect. Give that the amps are so efficient, require very little warm-up time and the fact that we can't keep burning our resources forever, class D has got to be considered as a serious prospect for the future...
