This is still a work in progress, but it's nearly done and it's verified on the breadboard. It's a simple A/B/Y splitter with a transformer-isolated output. What makes it different is that all the switching is done electronically. The A/B/Y selection is done with simple momentary footswitches that are controlling a flip-flop circuit. The flip-flop then controls a CD4053 to do the actual signal switching. It's all very 70's tech.
It also includes a switch to reverse the polarity of the isolated out - a very useful feature in some situations where you're mixing mismatched amps.
Here's what I have done so far:
- A-B_IsoSplitboard1.JPG (38.92 KiB) Viewed 4192 times
- A-B_IsoSplitboard2.JPG (39.43 KiB) Viewed 4192 times
You see, the pcb design I've done is 2-sided. It seems like it needs to be for it to be able to fit into this space without requiring a ton of jumpers. I was able to make this board with press n' peel, so you shouldn't consider it an impossible task to do yourself. The trick is to be sure it's well-aligned along two of the edges, and it should turn out fine. This layout is designed to fit into a 1590BB size box.
I'll upload the schematic and artwork after I get it boxed-up and have the final thing verified.
"Analog electronics in music is dead. Analog effects pedal design is a dead art." - Fran
why didn't you just surface mount all the parts? despicable!
I'm just a shy guy with an lovely, silky smooth personality 
, now it's my turn 
Ken