About a couple of years ago, being a happy recipient of the Parts Express Catalog, I saw the A500. At the time I was thinking of constructing The World's Finest Audio Power Amp (still a desire..) and, y'know, an A500 was cheaper than buying a chassis and power supply and plugs and sockets from DigiKey or whoever. So I bought one for sacrifice.
Then I thought - may as well see just how bad it is, and plugged it into my system (Linn Sondek LP-12/Rega RB300/Shure V15 MR; Linn Wakonda; Linn LK140; B&W 801-III) and - begod - it sounded better than the LK-140. Still did a few weeks later. Not only more relaxed pwoer, but better bass control. Maybe a little sweeter. Recognisably the same music, but.. nicer.
So I did the sensible thing, and bought 2 more (one per speaker, bi-amped) intending to keep the first as the sacrificial lamb. Had *serious* groundloop problems, resolved in time.
Just got an Integra DTC 9.8 preamp-processor. I expect to circumvent the groundloop solution by using the balanced outputs.. soon's I've bought more cable and plugs...
A whole new life - the A500s sound most excellent.
Thoroughly recommended.
Of course, my amp will be better - but don't hold any breaths
-- P