Testing Rig

From the vendor

The Testing Rig is a combo PCB that incorporates the Tiny Tester and Headphone Amplifier PCBs available from JMK PCBs along with a switching system that allows a user to put another effect into a loop, provide power and ground for that same effect, and also use an audio probe on the effect. This is extremely useful, especially if you’re looking for an all in one device for testing and troubleshooting effects pedal builds! The people behind JMK PCBs use this on every single effect we build, and so should you!