PRR: Thanks for the time and consideration. I think I had better either donate to the board, or send you something by PayPal!
Yes, the six larger diodes are 3A / 1000V. Or at least they were advertised as 1000V, I could believe that 800V is the most a person would want to deal with. The one smaller diode on the preamp board is 1A / 1000V (or it was advertised as such).
B+ in the amp is 495V.
It does work great as is! Unless this changes I don't intend to mess with a working thing. Your points on an amp full enough of fuses to be simply called a fuse box and two routes to the mall are well taken, and pointing out that these old Fenders (or a Kay, and these old Marshalls, too) are nowhere near the apex of engineering (yet they work well for what we ask of them) is not contestable. However, for my own personal education, and in the instance of serious problems with my amp:
-The CT of the heaters, I now am understanding that the CT is not a part of the heater loop that carries current, but rather just a branch. Checking into this, plenty of older amps have heaters with no CT, but the complaint is some hum -- so as a person could take two 100 ohm resistors at some point along the heater chain, and make an artificial center tap to ground. So it is not part of the heater loop that sees a steady current. Or so
I think...
-The PT HV CT going to the negative lead of the mains filters -- in an effort to have the rectifier side and the load (signal?) side of the amps share less of a common conductor (chassis?). Hmm. Never even crossed my mind. And I thought I was being a bit clever by separating the mains filter ground from the screens filter ground!
-As for the heater CT, I could run it, then, through a 100 ohm (1w?) resistor, and head it over to ground at the same point as the rest of the preamp grounds (seeing if I have got all this right)?
-I can put in a ground lug in right beneath the 3 prong socket for a dedicated chassis to IEC connection (as short as possible), if I feel I don't trust a shared grounding screw.
-Although I'm not ever really safe so far as transformer protection goes, I can probably do a bit better than I am now, although it is not necessary.
Your Champ, with minimal ground points, sounds extremely well thought out.
Your help is much appreciated, sir!
Edit: Donation has been sent to Prodigy Pro forums.