80srock

Does the Marshall have an effects loop? The nice thing about digital effects is they do not have to me ran inline. If you have an effects loop run the digital effects through it and the tube screamer in line with the guitar.

Parker guitars are setup like this. On my Nitefly my magnetic pickups are seperate from my piezo pickup. It has a stereo jack that will run the signals seperate. A 3 way switch that will let me choose between magnetic or Piezo or blend. Also a push button switch that lets be switch between using a single cord to one amp or a stereo cord to split to seperate amps. If you can get your hands on a parker wiring schematic this will have what you need and then some.