According to the MBL article, using 10 gauge wire is the first step to audio heaven
Just be careful or you WILL end up in Audio heaven......
Probably not too many Krell owners who went for 220 VAC operation.
Probably not but the amps do come with a 20 amp outlet, their stock power cords then change it down to 15 amp plug - to fit your average house here - for sales I guess.
All Krell owners I know use a 20 amp cord on a 20 amp circuit. I do with my FPB600.