How can I make the Reverb on My Marshall Valvestate VS100r footswtchable on and off?

I have a Marshall VS100r "hybrid" Amplifier and it has 2 channels of reverb. So I'm trying to see if there is a way to mount a 1/4" jack in the front or rear (preferably the rear) and use a Boss FS-5L footswitch (Latching) to turn the reverb on and off. I'd like to be able use 1 footswitch for both channels. Thank you so much in advance for your help, - DIY Dom

orksecurity7 years ago
If there's an existing SPST control switch, put the footswitch jack in series with it, using the jack's "no plug present" connection to bypass the footswitch when not present. Or don't use that connection, and put the footswitch in parallel with the existing switch. The former will let the switch turn it off when the panel has it turned on, the latter reverses that. If it's a DP switch, you'd need to have the footswitch control a relay which in turn gets hooked up to the existing signal path. That'll probably also produce less noise than using the footswitch to directly switch the audio, so you might want to do it even in ("2 channels of reverb" may be either stereo reverb or just two inputs to a single reverb; I don't know your device well enough to say which.) If it has only potentiometers... Basically the same idea; you're now adding a switch to the signal path. Rather than relay, a better answer might be turning a unity-gain amplifier on and off -- I'd suggest op-amp based since that's easier to work with than discrete components. Hope that helps get you pointed in the right direction.