I bought the Boss SD-1 PCB from General Guitar Gadgets as a fun build project. I don't have much experience building pedals so aside from a few IC buffer circuits and a couple of bypass loopers, this is my introduction to pedal building. I'm not sure how this will go but I've identified what I think are good candidates for modification within the GGG circuit and I'm socketing those locations. Last night I soldered the permanent resistors to the board and socketed all the resistors that I may experiment with. I'll do the same for the diodes and capacitors next. I missed a 1.5 M resistor at the start of the circuit because that's an unusual value that I don't have, then it dawned on me that it's just a pulldown resistor so I'm going to drop a 1M in it tonight and be done with it (dumb). I'm kinda following Brian Wampler's excellent article on the SD-1 and really playing around with it. I'm not really sure what op amp I'm going to use here. I don't have the stock one but I do have a few options at home. It's going to be socketed so I'll play around with those as well. This is a weird build since the GGG SD-1 board is shoehorned into their Tube Screamer PCB. Few of the values printed on the PCB are in fact what the circuit calls for and there are several components that aren't added to the final build.