09-18-08: Audiofeil
I can't think of a good reason to use class d amps with horns unless you're the adventorous type.
IMO you'd lose much of the "warmth" without the tubes.
Borrow some digital amps and give a listen. It may be your cup of tea.
But don't form your opinion until you give a listen to the ridiculously affordable Onkyo A-9555. Onkyo's design has some patented circuits to specifically address the problem of switching noise in class D amps.
Robert Deutsch reviewed the A-9555 for
Stereophile into a pair of very high sensitivity Avantgarde Acoustics Uno horn speakers. He makes special mention of how he often has to chase down hum and buzzes when reviewing upstream electronics because of the Avantgarde's sensitivity. When he hooked up the Onkyo, however, he asked himself, "Is it on?" It was. So unlike most, it can be a good match for horns. And its power rating should be a good match as well.
Unlike pretty much any other class D on the planet, *once it's broken in,* the Onkyo is known for a relaxed presentation and a smooth, engaging treble. Even the little summary blurb in S'phile's Recommended Components section compares the Onkyo's *resolution of low level detail* to tube amps.
I have one and have to agree. It reminds me of the high priced class A/AB amps (Ayre, earlier Rowland) more than anything, and replaced two highly regarded vintage amps--the Amber Series 70 and VSP Labs Trans Mos 150.