Wirewound pot for Rk

[dsavitsk]

I have some 5K 5W wirewound linear pots -- no idea why I have them anymore. I am building a guitar amp and was wondering if there is any reason not to use them for Rk on the output tube. The idea is that I can adjust for different tubes and different operating points without having to resolder and without reaching inside the chassis. Other than the issue that someone not familiar with the amp could cause damage, are there other reasons to avoid doing this?

[Miles Prower]

Originally posted by dsavitsk
I have some 5K 5W wirewound linear pots -- no idea why I have them anymore. I am building a guitar amp and was wondering if there is any reason not to use them for Rk on the output tube. The idea is that I can adjust for different tubes and different operating points without having to resolder and without reaching inside the chassis. Other than the issue that someone not familiar with the amp could cause damage, are there other reasons to avoid doing this?

There is one possible reason not to do this. These wirewounds might have too much inductance. It's something that should be checked out before you attempt this. Another reason not to do that is that the cathode bypass capacitor probably won't be optimum for all conditions of bias.

If you intend to do lots of tube rolling, you're probably better off using fixed bias.

[kevinkr]

The lowish dissipation rating of the pot might also be an issue depending on how much of the element is actually in circuit.