The power supply is kind of a PITA along with
the rear amp (which I would deactivate for the sake of a low noise floor, and it's full of obsolete shit) but they sound great. Beefy Bob made some great Pre's. I prefer the C1, or the 4000t but I got the C-4000 nearly as quiet and the numbers were so low you couldn't tell anyway.... The Power supply is rudimentary but doable.
I caution you though when dickin with the phono amp board (everything runs through it), if you wanker the selector switch, all bets are off. I've been trying to find a suitable switch but have not had much luck. That switch hangs off the board like a sore thumb and can be broken (you may have seen my post where the dude sent me the board and didn't pack it properly)... It's lays in the junk pile as we speak. Go slow, take lots of pics, and if you have questions, just ask. I bought a 25 pack of the new TI RC4136 opamps and I changed them all out, and Glen has some bypass cap tricks which help get the pre dead silent, which pairs well with a WOPL. Glen has done his share of them and I think he runs one (or 5). he's hoarding all the good shit....
Oh, the reason I like the C-1 so much is they make a rear plate for it to get rid of the cheesy RCA's they used on most all PL/Carver ... Plastic is for buying shit when you have no cash NOT for building good stereo equip...
Good luck