Wow, the underside construction looks gorgeous. Very neat, very clean (and very quiet in operation, i bet).
I noticed you used magnet wire for the ground bus. Any reason why? and how the heck did you strip off the dielectric? I still can't figure out how to do it well enough to get a decent solder joint. I own an original foreplay that i got from my uncle back in the day, but it's suffering from issues, so I'm thinking about rebuilding it for fun even though I don't have any need for a line stage. Maybe I'll buy or build some monoblocks some day...