So who wants to make a PEQ tone circuit?

anybody who has ever wanted to recreate a PEQ circuit has figured out that the potentiometers used in the original circuits are unique to Westone guitars and there does not seem to be anything on the market that matches their design. i have several Westone guitars that previous owners removed the PEQ circuitry.

as luck would have it, a group called Franklin Guitarworks has recently acquired a treasure trove of original Westone parts from SLM and they are gradually putting pieces and parts up for sale on ebay and reverb (and maybe elsewhere). the picture they put on the ebay listing caught my eye because of the different colors on the front and rear pots, just the same as i noticed on the ones in my guitar. so i was hoping they were the right ones. i ordered 4 of them.
i inquired about the pots but they did not know anything about them. i asked if they had a center notch and the answer was "no", except they actually do have the center notch.

well i think the right potentiometers have appeared. i got them in the mail recently and have been comparing them to the ones in my Prestige guitar and they seem like the right thing.

this one is installed on my Prestige 150


and this is the part i just received


the only difference is the last row of numbers/letter, (i do not know what the last row means, maybe it is a production batch number or something) but the other markings are the same.

i also looked through the forums for threads that discuss the PEQ setup. i found a description i wrote about the way the pots work in a thread from 2011

i opened up my Thunder II to check out the pots on the PEQ circuit to verify exactly the setup on the pots and how they function electrically.

i disconnected the wires and checked the pots with a meter, then made a little sketch...
(i measured the rear pot at closer 650K end to end, terminals 4 - 6)

so it turns out that the stacked pots are not identical/mirror images of each other. the pot to the rear has the resistance element completely from one end to the other, with a center detent.
the front pot has the full resistive element on only half the sweep of the pot, and zero resistance the other half.

this description tracks exactly with what i found when i checked the new pots with my ohm meter. I have not installed one yet to verify that they will do the same thing as the originals, but i am quite certain these are the right parts.



here is a link to the >>ebay listing<<

Great stuff Mike!
You're on a roll this week! 

Looks like another "sticky" is in order.

Thanks!

Oh yeah, you found some brand new PEQ pots!
It has been on the to-do list of my little guitar-electronics company for a while to recreate the PEQ tone control. Unfortunately this can only be done by ordering custom potentiometers with a custom taper and involves an investment of a couple of thousand Euro's.
In the summer of 2023 I want to map the pots and create graphs to send to the different potentiometer factories: Bourns, CTS, Alpha to see what they can do.
For funding I may want to do a fundraise on some big Matsumoku platforms.
But as I need to make a living too it will take time.
It is a brilliant tone control design. Not only for restoring Westones but also for new guitars.
Regards,
Bas Becu

i recently found a place that makes the correct knobs for the PEQ pots

>>reproguitarparts<<

they fit the pots from Franklin Guitarworks perfectly
it seems that there is only the 'gold' colored knobs at this time
they also have switchmaster knobs

Great find Mike, thanks!