Since I had a few NPN Germanium transistors laying around, I decided to build a NPN Ge version of a Tonebender Mk3 since the transistors had the right gain buckets and leakage for such a project.  I used an unknown NPN Ge transistor at Q1, an OC140 at Q2 and an AC128 at Q3.  Both Q1 and Q2 transistors had gains around 65-70 HFE and Q3 a gain of around 120.

This pedal is an illustration of the usefulness of the Guitar PCB 3PDT board, which I use nearly exclusively now due it’s wonderful utility and adaptability.  This is the best of this type of board out there, bar none IMO.  It has pretty much been my “go to” for wiring up pedals, no matter the vendor of the main board.  All one has to do, as in this case, is map out where all the connections to the main board need to go from the GPCB 3PDT board.

Of course I modified the circuit slightly by adding a trimmer to Q1/Q2 to attain the proper voltages as well as an external bias control to Q3, a feature I pretty much add to all my Ge based fuzzes due to transistor drift and the ability to change the fuzz characteristics of the pedal without having to open the back of the enclosure.  For some reason the first 10K bias pot had fried on me while playing around with the pedal for some unknown reason (after the pedal was working fine but before closing it up) so I changed it out to a 25K pot, adding a 1K resistor to the output like the 10K pot so the resistance of the pot does not go all the way to zero.  I did not have another 10K pot on hand to use.

Due to the amount of wiring required – four off board pots, including the external bias, and a trimmer, the wiring is somewhat of a mess.  Just difficult to tidy things up totally because of all the off board components.  I did manage to clean things up a little bit more compared to the gut shot before I installed the back plate to the enclosure.

I’ve got a couple GPCB main boards coming my way soon for future OD projects, along with more 3PDT wiring boards.

Top of Enclosure:

Gutshot showing the wonderful and useful GPCB 3PDT wiring board and all the wiring.