I've tried two digital amps in my system over the past 6 months and didn't end up keeping either of them. One was a SPEC from Japan and the other was the 2170. I tried them both with Devore Nines and just wanted to love them. I wanted the simplicity, the ease, the low heat and high power. I just found them to lack synergy and fail to energize the speakers the way I like. I've owned many other speakers in the past that didn't always sound different with a change of amps, or a shift from SS to tubes. I find these speakers to be very revealing and honest to what you put in front of them.
The Future of Audio Amplification
I have recently paired an Audio Research DS225 Class D amplifier with an Audio Research tube preamplifier (SP8 mkii). I cannot believe how wonderful and lifelike my music sounds. The DS225 replaced an Audio Research SD135 Class AB amplifier. Perhaps the SD135 is just not as good as some of the better quality amps that are out there, but it got me thinking that amazingly wonderful sonance can be achieved with a tubed pre and Class D amp. I have a hunch that as more people experience this combination, it will likely catch on and become the future path of many, if not most audiophile systems. It is interesting that Audio Research has been at the forefront of this development.