Solid State Guitar Amp Forum | DIY Guitar Amplifiers

Hi All,

I'm trying to resurrect a Peterson P75G (1980s transistor combo), and it's working and sounding great but lacking a footswitch. The P75G has two preamp channels, one for clean and one for distortion, but there's no way to switch between them using the control panel. The only option is via a footswitch into a 1/4" jack on the back.

I've tried a simple single pole jack and it works fine, but I'd like some kind of visual feedback (an LED) to show whether or not the switch is enaged or not. Does anyone know if there's a standard footswitch available I can use with the Peterson?

Thanks.

  Without modifications to the amp, you will need a battery in the footswitch to run the light.
You can modify your existing footswitch, or you can buy one already made, something like this: http://www.ebay.ca/itm/Voodooman-FootSwitch-1-Button-W-9V-DC-powered-LED-/380503784108

Thanks for the advice g1. What I hadn't spotted when I first posted is that although there's no way of switching channel from the amp controls there is an LED on the top of the amp that shows when the dirty channel is switched in. It's not quite as handy as having the light on the footswitch, but it works fine and the amp is both sounding (and looking) great.

Measure the voltage across the footswitch when it is in the open position.  Depending on how it does the switching internally (if it uses a relay) you could try using a very high intensity LED with a series resistor in the pedal to give you a state indication.  High intensity LED's can give quite a useful indication on very small currents, much less than would activate a relay.  If it's solid state switching it still may work but YMMV.