Improved Standby switching

[NorCalTuna]

When using the valve wizard standby with a center tap, is it necessary- or just more effective- to put a resistor on both sides of the secondary? It seems it would work with only one, but since the center tap is the return path, the resistor would only effect one "phase" of the transformer (please correct me!) and the resulting humpy DC would be of alternating voltages.... which again, is working but not as effective? Can you put the resistor on the center tap and switch it in and out of there?

Thanks!

ps link:
The Valve Wizard

[Wilder Amplification]

When using the valve wizard standby with a center tap, is it necessary- or just more effective- to put a resistor on both sides of the secondary? It seems it would work with only one, but since the center tap is the return path, the resistor would only effect one "phase" of the transformer (please correct me!) and the resulting humpy DC would be of alternating voltages.... which again, is working but not as effective? Can you put the resistor on the center tap and switch it in and out of there?

Thanks!

ps link:
The Valve Wizard

Yes you would have to interrupt both phases and use a resistor on each side with a full wave center tap rectifier. I personally don't see any reason why you couldn't just do a single resistor/switch on the center tap leg. Although this wouldn't be the "textbook accepted practice" it would most certainly work as you're just simply interrupting the other side of the circuit instead.

I also don't see what the issue would be with using a DPST standby switch with two resistors on the "phase" leads.

[NorCalTuna]

Thanks Jon! I'll use them on the secondaries as I will be using the "bias" tap for other things, so the center tap won't be a good idea. soo...

The other thing I was concerned about was if the bias circuit was something to stress over. Should it scale (capacitively coupled to secondaries after resistor and then reverse biased) or can it just power up full voltage (from the bias tap and reverse biased) with the tubes coming on slowly. Fenders etc. do that-full bias at standby- but is that good practice? Having those resistors there allows some current to pass, and the tubes will be operating to some point; I'm thinking it'd be a good idea to let it scale as it's safer to under than over bias? ie, wouldn't full voltage on the bias potentially make the amp run like a soggy, massively current limited class a thing in stdby when all the voltages are way down? TIA!

[Merlinb]

is it necessary- or just more effective- to put a resistor on both sides of the secondary? It seems it would work with only one

Yes it would work with only one. I just like symmetry.

The other thing I was concerned about was if the bias circuit was something to stress over.

It doesn't much matter what the bias supply does, just so long as it doesn't take too long to reach working level when you close the standby switch (otherwise the HT fuse may blow) as the valves are momentarily underbiased. Luckily, this is rarely a problem.

However, if you were to put the improved standby swith in the CT of the transformer then the bias voltage would go more negative than usual (during standby), potentially exceeding the bias cap ratings!

[NorCalTuna]

Hey Merlin! Thanks for all the resources, I'm gonna grab your books! (When is the power section one coming out?)

I've got dual poles on the switch i'm using so that will be gravy- and symmetrical, like a Reich piece : ^) Thanks again for clarifying the bias!