Fender Bias - adjustable

[Iain T]

Morning!

One of the changes I'm making on my current build is a move from the fixed bias (22k to ground) to adjustable. On RR's site he has a 10k with a 25k bias pot so the mid-point of that would be the stock bias value at 22.5k.

I'm struggling to source a chassis mountable pot (i.e. one that can bolt through from the outside of the chassis) in 25k, I can only find a 10k one.

So, my question... do I replace the 10k fixed to ground with a 18k giving a 18k to 28k range or opt for something that allows more skewing to hotter/cooler?

It's a Princeton based build so I'm not after super-hot power-stage!

[Bieworm]

Maybe look into something with a rotary switch and some fixed bias points?

[JMPGuitars]

Maybe look into something with a rotary switch and some fixed bias points?

...or a combination of that with the 10k bias pot. Or, two bias pots in series.

[Iain T]

My assumption here is that I'll end up fiddling with the fixed resistor. The standard 22k might be about right but I'll see what I get out of it with UK voltages.

I've had as high as 265V and low as 190V out of the wall recently - although the low voltage was storm/tree related!

[Big Swifty]

I’ve used these on my Princeton and Vibroverb clones:
https://www.tedweber.com/wp253l-slot/

[JMPGuitars]

If you're good with a rotary tool, you can turn any pot into that style.