Guitar Pedal

An overdrive pedal built as a birthday present for a friend, and designed from the circuit outwards rather than assembled from a kit. The gain stage is a TL072CP, and the whole circuit was simulated in LTSpice first so the clipping behaviour and frequency response could be looked at before a single part was soldered.

From the simulation it went to a perfboard layout, planned hole by hole so the build had a map instead of improvised jumpers. The op-amp sits in a DIP socket rather than soldered down, which is what made it possible to audition parts in the finished pedal: I played it with a JRC4558 in the socket as well — the chip most classic overdrives are built on — and kept the TL072CP. Switching is true bypass on a 3PDT footswitch, which takes the circuit completely out of the signal path when it's off rather than leaving it buffered.

The enclosure is an off-the-shelf printed design, not mine — the work on this project is the electronics, and the part worth reading is on the inside. Hand-wiring a perfboard this dense turned out to be slow to build and fragile to change, which is why everything I have built since goes onto a PCB.