Harvestman Black Locust Eurorack Guitar FX Module the improved successor of the old Stilton Adaptor is a four-channel guitar effects pedal adaptor for your synth, using each channel as a FX send/return for one pedal. It offers gain adjustment and a dry/wet control per channel. Alternatively you can use each channel as a guitar pre-amplifier.
With no external input signals, the four pedals can operate in a closed feedback loop, self-generating audio signals that are impossible to directly control - only influence.
If a Black Locust's channel is to be used as a Send/Return, connect a guitar pedal with a 1/4" insert cable - on one end it must have two mono plugs (TS) and on the other a stereo plug (TRS). The tip (red) is connected to the pedal's output and the ring (white) is plugged the effect input.
Now use the 3.5mm input and output sockets to use the pedal with the modular system; set the level with the Gain potentiometer and the effect amount with the dry/wet control.
If you just wanna amplify an electric guitar or bass guitar, to process it by the modular, connect the instrument with an unbalanced 1/4" cable.
Further modules like a matrix mixer and a programmable quad VCA/envelope follower/signal router, each designed to create a "feedback console" with the Black Locust which will render possible controllable feedback paths between the individual channels and effects. Very unique idea.