Not too long ago, I had my system plugged into
two Double Conversion Liebert UPSes. Whenever those units were plugged into the wall I always heard some noise coming through the speakers. My system sounded the best with the Lieberts when I was running completely off the battery, but I didn't get much listening time that way.
In the end I just went back to the wall, but sometimes these units come up used on the cheap, so the experiment was worth it.
I've read elsewhere that the Elgar 6006B is comparable to the Accuphase units, with a few mods of course, and on occasion they show up cheaply on evilBay.