Thank you everyone.
Elizabeth, yes, if it is so common I am a lot less worried.
Stingreen, obviously it IS wearing me out :)
Winoguy, I don't think it's 60Hz, it sounds a lot higher, but I'm wondering about a harmonic? It could be something else, of course.
One interesting thing about this, after lifting power cord grounds, trying all the power clears I could find, changing speaker cables etc etc ETC, is that it is very responsive to the kind of interconnects hooked between the pre-amp and the amp. In fact, the buzz is a lot louder if the amp is on with no interconnects hooked up to it, and quiets down some when I connect something to it. It can also be made louder by BAD interconnects. So, I should probably keep exploring (and spending, oy
) the interconnect issue.
Thanks everyone for chiming in. The immediate issue really is, if sonically I'm OK living with this, will it damage stuff downstream (ie the speakers)? If indeed it does not, there is much less urgency to this.