I owned a GFA555 for several years and it was OK. I traded down to a GFA 545II and recently swapped it out with a B&K Reference 4420. Huge differnece in sound quality on the B&W. Much better midrange, vocals crisper, bass deeper and more refined. The B&K wasn't that much more expensive either, but I was shocked at how much better performing the amp was. You can find them here for $550. I have also had good luck with a C-J MF-2200, and there is a MF-2100 up for sale right now at $525 if you only need 100wpc. Again, a much better choice than the Adcom, IMO. I would look for something a little higher-end if you can at all afford it-just my $.02.
