Preamp tube cathode resistor switch

[WRC34]

Howdy y’all

Pardon my ignorance if you will, but I’m wondering about installing a switch in a new build which would enable the cathode resistor of a preamp tube to be changed from say 1K to 11K without any loud popping, etc.

I know cathode bypass caps can be put on a switch, but in this case it’s the resistor (and thus bias of the preamp tube) I’m interested in varying. The amp will have a separate, dedicated input and volume control for V1 and V2, allowing the player to plug into V2 and leave V1 out of the equation for less gain/crunch.

My idea is to use a SPDT On/On switch which on one side would simply connect the 1K resistor to ground and when switched would put a 10K resistor in series with the 1K to ‘cold bias’ V2 for a more desirable/controlled overdriven sound when using the input for V1. My pea brain says since there would always be a ground connection this would allow me to cheat the loud pop that would otherwise result from this kind of switch/circuit being implemented.

Anyone care to point out why this hair brained scheme wouldn’t work the way I’m thinking?

Thx !

[roberto]

Changing Rk will change the working point, so the voltage at the plate, so there will always be a pop unless you mute the signal downstream.
Why don't you add a scratchy pot instead, to set Rk as you want?

[WRC34]

Nothing is out of the question provided it will work! Do you call it a scratchy pot because it will be scratchy sounding while being adjusted? (But hopefully quiet once set?)

[thetragichero]

dc on pot = scratchy while being adjusted
"crackle okay"

[roberto]

Yes, scratchy when adjusted and quiet when set.
Like old Marshall presence pots.

[WRC34]

Fantastic, thanks guys!!