I was driving my Reference 3.5's with a Bryston 14 B SST and tried a used Axiom A-1400-8 which is an 8 ch class D. I also decided to go 5.1 surround. With the Axiom I was using a low pass filter set at 55 Hz to drive the second voice coils of the Reference 3.5's. This was the most amazing sound I have ever heard. The Axiom sounded much better than the Bryston did in this configuration. The problem I was having was a mechanical relay noise from the one unused channel. I was using 2 ch rear, 2ch front main, 2 ch second voice coil and one ch centre. That left one unused and the clicking relay drove me crazy and I sold the amp. I'm kicking my self now, because that was one very sweet combination. The Axiom amp is very quick, detailed and extremely powerful, it also had the best high end of any amp I've owned. It was very detailed but not at all bright or sibilant. The new Axiom is available in 2, 3, 4, 5, 6, 7, or 8 channels. I will be getting one soon. I bought an EMOTIVA XPA-5 to get me by for now, but it has a very hot top end with these speakers and is somewhat sibilant.