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Finished a PURP finally after having had the PCB for a couple of years with a total of 3 GPCB boards in the project for a mini combo build. Just wanted to build other pedals as I already have a few treble boosters, both Si and Ge, so I waited until I started running out of other projects. Of course I put my own flair on the project. Instead of the Grit trimpot off the emitter side, I wired up a 10K external pot instead so I could have an exterior control for the “Grit.” I really like this mod because I can add the slight grittiness to the sound and then back it off for a standard treble boost without opening the back of the pedal.
Second, I substituted a Rototone for the C2 input cap for additional flavors of mid boost, the “Mids” control. In positions 1-4, I placed 6.8n, 15n, 27n and 39n caps so that in parallel with the standard value 6.8n cap I would have input capacitance’s of ~14n, 22n, 33n and 46n close to standard values. A 22n input cap is standard for a Hornby Skewes treble booster and a reported Blackmore mod was changing that to 47n, so this booster has it all! For a third mod, I also placed and 82n cap at C3 to give more of a full range boost (close to 90n total capacitance in parallel with the stock 6.8n cap).
I did run into one glitch right after finishing – I got nothing from the pedal including no bypass. I figured it must be the input or output jack, and of course it was a defective input jack, so I replaced it and the pedal fired right up. Unfortunately, in the process of pulling off the input jack wires, the ground wire detached from the 3PDT wiring board (broke off). I spent some time trying to clean out the solder eyelet on the board and finally gave up after awhile, just soldering the wire to another ground eyelet. I was just a bit ticked off that a bad component delayed the completion of the working pedal, but that is one of the “joys” of pedal building. Pictures below.
Exterior Top
Gutshot.
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