External Effect Loop

I got side tracked with a little project to build an external effect loop. I was trying to decide if my next amp should have an effect loop or not but then I thought the best course of action would be to build an external one that could be used with whatever amp I wanted. I would just need to add in and out jacks before the PI.

I have it built and am currently tweaking the schematic a bit. It’s similar to a Dumbleator but a little different.
It’s built in some sort of video camera power supply box.
It’s not pretty but it works.