Circuit-bending: DD-666

During 2015 my attention was grabbed by Yamaha's long-running series of 'DD-x' drum pad machines, particularly the ones manufactured during the early-mid nineties. I learned that (with a couple of notable exceptions) these make excellent candidates for circuit bending and I happened to be looking at that time for a distorted, nasty new rhythmic sound to be at the heart of Non-Bio.


The model I eventually found was a DD-6 from all the way back in 1990 and straight away I found that by shorting out pins on its processor I was altering the rhythms it produced in unpredictable ways.

DD-666 processor

Photo taken early on in the project. After a couple of sessions, there was a veritable rat's nest of cablesspewing from both the chips.

Unfortunately my lust for reckless experimentation soon got the better of me and I made a critical mistake, allowing a 9v cable to come into contact with a part of the circuit board only intended for 4.5v - this had the unfortunate effect of damaging one of the chips and rendering the four drum pads on top of the machine unusable. I considered throwing the machien away and beginning the project again from scratch, but with some further work I discovered that almost-as-good pad-like effects could be generated by shorting yet more pins on the ROM chips, so I wired in a bank of six push-button switches to trigger these noises. I also wired in a further circuit board taken from a voice-changing megaphone toy in order to further mutate the sound output.

DD-666 almost finished


Footage of an early test of the DD-666, together with a Kaoss Pad Mini and a Chimaera effects processor.