AC30 top boost extra knob function idea 10k resistor as pot

[steveo7868]

I have a weird idea to add a knob to the typical vox ac30 top boost tone stack, because I have a chassis
that has a faceplate for a mid knob, and I dont really want to change the tonestack that much
to make it a true TMB, what effect would there be if that extra 10k resistor from the  wiper of the bass pot
was made into a 10k pot? I did try this on the bench and it seemed to do something... possibly affecting the mids..
to be honest I would rather build it stock without this knob but, I just wondered about this idea..

[jordan86]

Your answer, and a world of experimenting possibilities, lies here:

https://www.guitarscience.net/tsc/vox.htm#

You’re asking about changing the value of R2 in this scheme.

[pdf64]

I’d use it for a switch to alter the coupling cap value from the input stage’s anode. That will bring in more mids, so it’s appropriate!

[steveo7868]

Awesome answer and sure enough it is a mid pot and all the way up its stock, or if you want more mids it looks like a 25k pot would be the ticket