Mod Marshall pedal-90012 to work with 4100 dual reverb.

[Offcenter2005]

I was wondering if it is possible to rewire the 90012 foot switch to switch channels and turn the reverb on and off with my jcm 900 4100 dual reverb. As of now the fx loop button does nothing. Thanks in advance.

 

[Purgasound]

Yes, although you will likely lose the LED function.

The switches just need to open and close a connection between the tip and sleeve for the channel switching and the ring and sleeve for reverb to operate on a 4100/4500 amplifier.

The default position shouldn't matter.