standby switch

[Gaz]

On a more serious note, I always, just wire a 220K/2W 'bleed' resistor across the standby switch. It still completely mutes the sounds, but let's a little voltage creep through. I also try to put it in the AC line when practical.

[pdf64]

My (current!) preference is for the standby switch to be across a ~22k >2W output tube shared cathode bias resistor.
Not a complete mute but a little cathode current still flows to avoid cathode poisoning, caps stay at full charge thereby avoiding current surges, and just a few tens of volts across the switch.
If a complete mute is required then a DP switch can be used, with the other section used to ground the signal at a suitable point.

[Gaz]

My (current!) preference is for the standby switch to be across a ~22k >2W output tube shared cathode bias resistor.
Not a complete mute but a little cathode current still flows to avoid cathode poisoning, caps stay at full charge thereby avoiding current surges, and just a few tens of volts across the switch.
If a complete mute is required then a DP switch can be used, with the other section used to ground the signal at a suitable point.

Any reason you don't use a higher value, lower wattage resistor for a full mute? Say, 100K?

[pdf64]

Signal voltage on g1 will cause the cathode voltage to rise.

I think very high ground reference resistor values may allow the cathode voltage to increase, possibly approaching the limiting value for Vh-k and Vg1 (-k).

So, best to keep the cathode robustly tethered to ground.

Also a complete mute seems less useful than a tiny bit of signal output, eg when setting up.

[Gaz]

Gotcha, thanks! I think maybe 10k be a good compromise. Resistor could still be 1/2W. I do have to disagree about the full mute, I still find it very useful.