Those padshop sessions where you just want a note held long without always having to press down on the keyboard…
i have a remoteSL controller (no mk2) and i just found out that if i stick my headphone plug into the sustain pedal slot, it acts like i am pressing down on a pedal:) loool , kewl!
jokes aside, there is a little truth in that.
Just plopping a electronically delicate thing as a pair of headphones into something that might have control voltages that burn your headphones out in a millisec is not a good idea unless you want to buy new ones for no particular reason. Now in this case there are no dangerous voltages for a pair of headphones in a pedal input, but I’d try with some el cheapo instrument cable I got years ago that I don’t care about. And I gotta ask you what in the world were you expecting from your experiment?