I've been interested in circuit bending for a while, but have never really done a permanent mod to one of my keyboards until now. I'd just like to share this one with you, as I think it's quite cool and could be useful.
The keyboard I used was a Casio PT-87 that I bought for 50 pence and a village fete. It's quite old and doesn't have very many cool voices or accompaniment like the SA series (I've also got a little SA-1 which is my favourite and two SA-35s) but what it does have is a pitch pot on the back.
Naturally, I opened it up and started poking wires around and that's when I noticed that touching either side of the pitch pot lowered the pitch, but touching them together and bypassing the pot made the pitch higher. Thinking that was quite cool, I decided to stick some things on the outside of the case that would make this easier to do.
I had originally planned to attach a wire to either side of the pot and then poke them out of the speaker grille thing, but that would have been a bit too
ghetto. In the end, I decided to get some self-tapping screws and just screw them through the top of the speaker grille and then run wires from each side of the pot to them.
It now works nicely and when used with a sustained instrument like the trumpet I can do lots of cool wobbly effects.
Hope that was vaguely understandable