redplating in power section - baffeled could use some help

[JazzGuitarGimp]

I see Martin and I were crafting our responses at the same time.

[gui_tarzan]

Ok, that makes sense but it sure seems unconventional and yes, I would definitely put the switch on the filter cap section, not the bias supply.

[martin manning]

But, as Tubeswell pointed out earlier, as described (CT grounded, bridge not) and the standby open, it's a half-wave rectifier feeding the HT, and the bias supply is floating.

[JazzGuitarGimp]

Yes, I missed that. Thanks for pointing that out, Tubswell and Martin. So, at the very least, a DPST standby switch, that interrupts both halves of the HT secondary is in order.

[Littlewyan]

Or put the standby switch after the rectifier. Just thought I'd add another option to list .

I can see now how the PSU is working. Altho in my opinion its a bit more complicated than it needs to be, but thats just me, its your amp. Why did you decide to use half a Bridge Rect instead of diodes mounted on the turret board? (assuming you used a turret board)

[martin manning]

So, at the very least, a DPST standby switch, that interrupts both halves of the HT secondary is in order.

Much better to have bias voltage present in standby any way you do it. Just move the bias to the hot side and rest easy.

[Ned]

COngratulations Lou it works as you say and should have the bias connected on the transformer side of the switch. This bias circuit was discarded by almost every amplifier manufacturer , both Hi Fi and guitar, that I know of because it is very hard on the electrolytics and its failure could allow full AC from the transformer to get into the output tube grids..this while many parts are failing along the line. A little transformer and a few parts to build a little bias supply will solve that problem.
We also have not solved the red plating issue he says all his amps have.
My guess would be that for the 6V6 and EL34 which he is running at 35% over the manufacturers DESIGN MAXIMUM plus an additiona 10 volts at the venue's voltage there should be no question why and the only answer is take them down to about 300 volts. The EL34s red plating at that votage could be a screen and or bias voltage issue.
Ned's rule #1.. Build a stable amp then make it do what you want it to.

[Ned]

That should be ....6V6 and EL 84....OOOps