So I wired up my version of this control to a 9 way rotary switch. With positions 1 - 3 offering tones like turning up a tone control with a .022 cap, position 4 bypass, and positions 5 - 9 putting a progressive load across the output to lower the resonant peak of the pickups. While prototyping I was getting some very, very cool sounds but I definitely need to customize the cap values. Position 9 was pretty dark, probably wouldn't use it, and 5 was very subtle. But positions 1-3 and 6-8 were all usable different tones! Once I fine tune it I'll post some pictures, schematic, and cap values...

Similar to a Varitone but actually simplified. A Varitone uses a choke (inductor) to create a notched response. No inductor for this circuit making it smaller and easier to solder.

Those switches are off the hook! Yep, the Varitone does suck some volume at certain settings but this circuit doesn't because of the omission of the inductor.

You know, I've been a set the tone knob on 10 and rock out guy for the vast majority of my playing life. But suddenly I've become obsessed about wrangling as many tones from the guitar itself as possible. Shifting the resonant peak like this circuit does isn't something which can be approximated by tuning the tone knob on an amp. In my college band, I'd simply load up 3 guitars and when I wanted a specific tone I'd swap out axes. But these days its one guitar and a back up. As such, having a bit more tone control, coil splitting etc is extremely nice as it allows certain voices that you can switch in and out for a song or 2.

I'm extremely intrigued by the tonal possibilities of expanding this circuit and fear I may be getting sucked down a rabbit hole! I mean shifting the resonant peak with caps in parallel is just the beginning, coupled with a high pass circuit (capacitor in series) you could shape a pickups output in some extremely radical ways...

Ok experimented some more with cap values...and made it unusable!!! Mud city. I need to revert back but I fear I may have burned out one of the caps. Now I'm thinking rather than 9 positions, I'd prefer a dual pole setup with 6 positions allowing 2 presets like a traditional tone control, 2 resonant shifts, 1 bass cut position, and bypass. I've got a handful of 6 way 2 pole switches but nothing tall enough for the PRS. Doh! I tried to figure it out on the 9 way, but don't see how to do it without a second pole. May have to go shopping...

Do you have a Electrician's License!!!
Terry