What to build with 580VDC B+?

[tedmich]

many of the AX84 amps have a bias supply off the HV tap, even a couple with variable bias to both halves of a PP.

[defaced]

I've tried bias off the HV, and it works, but I was using a full wave bridge rectifier and I had to have the standby switch on, which was between the rectifier and the first filter cap, to get continuity. I didn't like that arrangement for a couple of reasons so went with the seperate transformer. If I'm thinking about it right, with a CT and a full wave rectifier (like on the AX84 designs), you won't need to have the standby switch closed to get bias.

[tedmich]

I think you're right, but with no HV (in standby) you really don't need bias either right?

[defaced]

When I work on the amp, I'd prefer to not have the HV on while I measure bias voltage, and I'd also prefer to have bias present before full HV is developed on the plates and screen of the power tubes. Also, it bothered me that the bias circuit is then reliant on the power amp and preamp paths to ground to complete the circuit, and that the bias would fluxuate based on that path to ground. Too many variables for me to process and figure out if they're important or not. Long and short, I'd just prefer to emulate the behavior of a PT with a bias winding.