Has anyone done a mod of the Zapper using a trs jack to an expression pedal for the pot controlling the sweep?
Thank you for your adviceIt's a great idea, but very risky. The FREQ pot connects directly to the inverting input of an opamp. That connection needs to be short, a few cm or less. Otherwise, you'll end up with an oscillator or a radio receiver. If you are serious about remoting the FREQ control, then install an LDR in place of the FREQ pot and use an Exp pedal to modulate the brightness of an LED. Or build this board into a wah pedal shell. Another way to do it, and it would be a major redesign, is to use a variable-gain amp like an LM13700 in place of IC2.4.