This custom pedal built for a Peavey 5150 amp was created to incorporate the channel select switch with an FX loop . Combing these two switches into one allows you isolate your pedals with your clean and dirty channel. The design included here is for the original 5150, however the design can be tweaked to fit just about any amp with a channel select input. I wanted the combinations of clean, drive, and loop activation to be fully user programmable.
Switch explanation:
The foot z.0aswitch controls the overall state that is programmed with toggles. Default equals State 1 (LED off) and State 2(LED on).
Left toggle switch(SW1) determines if the loop is off/on with State 2.
Middle toggle switch(SW2) determines if State 1 is Channel 1(C1) or Channel 2(C2).
Right toggle switch(SW3) determines if State 2 is Channel 1(C1) or Channel 2(C2).
Schematic_Logic_table
With this combination of switching you can create all the state variations you would like. This same schematic can be used as a simple looper with any amp. If you would like to mod this design specifically for your amp you can do these by finding out the functions of each tip and ring. I have seen a couple different variations of these. In our case here the tip equals 9V, ring equals NO switch, and sleeve equals ground. In all cases I have seen the sleeve equal ground. Sometimes the Tip equals a NO pull down switch, sometimes the ring equals NO pull up switch. Using a jumper wire, volt meter, and stereo cable you can determine what the tip and ring are configured as.