Positive ground - Negative ground, conversion dilemma

[GREEN FUZ]

I`m in the middle of designing a Tonebender MK1 layout on stripboard. The plan is to incorporate a switchable Crybaby circuit to get a %^&*ed Wah sound, without the pedal. Can you see where I`m going with this? Sort of Mick Ronson in a box. No gags please  .

Problem is, Tonebender is Positive ground while the Crybaby is Negative. What do I do? Convert the Tonebender section or the Crybaby section? For the time being I`ve made the decision to power the pedal by battery ,so if I leave the Tonebender as is, it wont have an impact on any pedals using a shared power supply.

I`ve read that converting Fuzz-faces to Negative ground can have issues. I guess the same thing might apply to a Tonebender.

Any advice?

Also, where the hell do I get a 660mH inductor in the UK?

[R.G.]

The problem is the "fake" ground inversion, where you don't change the polarity of the active devices. This is only a problem with germanium, where what you can get is only PNP in most cases. You can very easily change the wah circuit to positive ground by using PNP transistors and reversing the direction of every diode and polarized cap.

[rm -rp ./Matt*]

Couldn't you add bipolar power board to it, send the +9v to one board and the -9v to another?

[R.G.]

Put a charge pump inverter in it to make -9V out of +9V. See the article at GEO. One IC and some caps.

[GREEN FUZ]

Thanks guys, I hadn`t thought of that option. I`ve had a look at the charge pump inverter and while it looks fairly straight-forward I`ve decided to reverse all the polarized elements of the wah and see how that works.