Concentric Pots in tone stack?

[Fred G.]

I have a much-molested Allen Accomplice I built back in 1999 - This time around, I am (once again) fooling around with a "Dumble-style" tone stack. There is no Midrange control on this now "vintage" Accomplice; I want to add one. Is there any reason in the world I could NOT use, say, a concentric 250/250 pot in the treble hole for Bass and Treble, and plop in a 100K in the Bass hole for a Mid control? Any caveats, pot sources, other ideas all very, very much appreciated.

Thanks in advance - Fred G.

[Chuck H]

Concentric pots in desireable tapers and values are tough to find most of the time. Might be easier to use push/pull pots for the bass and treb controls and have the switches control midrange options (as in cut/boost, or whatever you come up with).

[pdf64]

Yes, sourcing the pots in suitable values and tapers (and also decent knobs!) is the issue. If you can find them, remember that carbon track pots are made from kits of parts, so if you can find then from the same manufacturer / range, you can swap tracks between them. eg bend back the tabs, take back shells off of 2 pots , swap tracks over, refit back shells.
Just did this with a CTS 1M push pull pot and a plain 100k pot, to create a push pull 100k pot.
UK manufacturer Omeg used to make dual concentric pots but the UK supplier that stocked them went out of business.
So if no luck with anything else, you could try contacting Omeg.
Pete.