i've built a feedback looper and i used a led and 9v battery. i'm now going to build an A - B Switcher and want to use an LED on each channel. I want to build the pedal so that the led's only work if leads are plugged into the box.
does anybody know how to do this?, i reckon i need to use a stereo socket so that when a mono jack goes it the circuit is complete but do i then need to use a supressor to avoid mains hum?
Get a stereo jack - wire the "ring" conductor (that is, the one that isn't on the mono jack) to battery - . Then, when you plug in, the battery minus will connect to ground, completing the circuit and allowing the LEDs to light.