I owned one for quite a while and only sold it because it I needed more power for my new, larger speakers . The sound was spectacular and I really did not want to let it go. I replaced the 100.2 with a 150.2 after using a buddy's 150.2 on a trial basis for several weeks. Despite some reservations about the 150.2 I published on the A'gon a while back, (after a flawed A-B comparison between the two amps), I have really found the 150.2 to be equal to the 100.2 while running cool as can be. The 100.2 has a slightly more tubelike presentation--warmer thru the midrange, totally grainless but with less authority and control in the bass than the 150.2. The newer 150.2 gives up only a little in the mids, being more neutral and clean but otherwise is as good or better than the 100.2 it replaced in all other respects. As a digital switching amp the 150.2 runs much more efficiently and, I suspect, is more durable over the long haul due to the low operating temperatures. I have to say that for my setup the 150.2 is really the better choice and the fact that it runs so cool is icing on the cake. Plus, the 150.2 doesn't have quite the cult following of the 100.2 and can therefore be picked up for the same or less money on the used market.
Audio Research 100.2 amp
Why didn't this amp receive more attention when it was in production? I recently acquired a pre-owned 100.2 for my second system and was very impressed with it's performance. Much more pleasant sounding than many other solid state amps I have listened to with a very nice, grain/grunge free, almost tube-like midrange and excellent bass/treble. Musical, smooth, resolving without sounding etched or aggressive is a very good way to describe the overall sound of this amp. Anyone else cares to agree/disagree?