Thanks!
It compares very well to the Harmon/Kardon HK670 that was my main receiver, well, up until this came in the house. Even more resolving, but without any sense of grit or over-sharpening; mostly subtle but very welcome improvements. I had the opportunity to try it before buying it, and while I was half-afraid that it would exhibit some of the overly warm and smooth characteristics I've previously heard in McIntosh amps, this was nothing like that.
Probably not coincidentally it looks little like stereotypical McIntosh equipment. My Heathkit receiver, with its black glass panel and blue-green lights, looks more like a Mac than the Mac does. Heh.
Right now the left channel is occasionally fizzing and dropping. Since a couple of the pots are a little noisy too, I'll strip it down and spray DeOxit on things before starting to worry. The previous owner took excellent care of it and it's in fantastic shape, so I'm going to assume that any problems are the natural consequence of age and the insidiousness of household dust.
The MAC 4100 is also much more susceptible to household static than my other equipment is (headphones crackle when I roll my office chair); will running a wire from the amp's chassis to ground on the power outlet take care of that?
