+++I have a B&K ST202 amp. Is the moscode an upgrade to my amp??+++
IMO, yes. A Moscode 600 replaced a B&K ST140 years ago. It was a step up, with some of the typical differences between tube and ss coming into play; eventhough the Moscode is essentially a ss amp (with a tube driver), and the BK was considered to be "tuby" sounding. The Moscode sound will actually be more "neutral" tonaly, but not as far as texture. The moscode will have larger, more rounded images, with more dimensionality. I found the B&K sound to be drier, but with a darker hue. This, of course, in my system. I hope those descriptions help in some way. Is it the best amp for $600 with the qualities you describe. IMO, no. A Conrad Johnson MV50 comes to mind. Or, if you can stretch the budget a little more (I hate when posters say that), for me, this is the one: http://www.audiogon.com/cgi-bin/cls.pl?ampstube&1297226361&/Dynaco-Mk-Iii-(Two)-Fabulous-new-build
Good luck.