It turned out it was originally just a zener diode that blew, but when he was messing with it at the meet he accidently shorted the (solid state) rectifiers and blew them too so he replaced them as well. I think he said the replacement rectifiers are higher quality ones that has been used in some past Cary equipment.
It's sounding good with the HD800 as I expected but my biggest surprise was finally trying on the speaker taps with some old speakers I have. The speakers are nothing fancy, just some mid 90's JVC 2.5 way towers I got from a garage sale for $20, but the amp drives it surprisingly well for only 1.5 Watts or so. Granted, they're tower speakers in a small bedroom, but I was still quite surprised.