I put the Gakken SX-150 MKII into an enclosure and broke out some of the ins and outs.
Some bad video of the bad noises…
Flush with hubris I added MIDI out to my Volca Beats (did the capacitor mod too). 
Used my audio breakout box to test the output of a cheap thrift store metronome.
And used the breakout box to test my 1/4” mono cables. 
But then I needed to make an expression controller for my Korg DS-8 and the breakout box failed to be useful because the Korg uses a TRS cable for the expression controller… I’ll be making a V2 breakout box soon that uses TRS jacks instead of TS. 
So I made up a box with TRS out for the expression controller. Just a box with a two switches (one momentary) in parallel, hooked up to a TS jack for the damper pedal function, 100K pot hooked up to a TRS jack (connect ring to wiper of potentiometer, tip and sleeve to either end of the resistive element). Two other momentary switches wired to TS jacks for the prog. up/ass. and down pedals, no point really connecting them but hey). You can already control tremolo and wah with the joystick, but that always springs back to center, this pot allows you to set various values. Damper pedal allows more sustain.
You can assign various functions to the expression and accessory switches.
Bad noise video:
Anyway, having fun I suppose.
