Oberheim LeDX

YouTube via rolandsh1000

"Short demo of a modified Oberheim DX. The mods are: moved Pitch pots, added Decay pots, new Volume sliders, and all controls have integrated LEDs.

The great thing about the DX is that it has a pretty open architecture and the big control surface. The uP generates trigger signals for each voice channel that are pretty easily accessible. The control surface, however, only had volume sliders and the pitch control was put on the back of the unit where you can't see what you're doing.

So in this DX, I added controllable Decay to all channels by utilizing the preexisting holes in the PCB. I also brought the stock pitch controllability to new Pitch pots mounted on top of the unit, where you can see what you are doing rather than reaching around the back.

As you can tell, the most obvious thing I did was to use potentiometers that either had or could integrate LED's. I was inspired by CMS's Arp Lumina who swapped out all the sliders on a stock Odyssey for ones with integrated LEDs - do a websearch and find the pics - it's a great mod because it looks cool AND improves the functionality! Anyway, these type of pots are all available at Mouser, but you can't just plug and play with them. The sliders all have center detent, so you have to open them up and remove the ball bearing & spring from the slider. I also had to Dremel out some of the DX's upper panel PCB to make them fit where the old Noble sliders were and adapt the mounting thread holes. The rotary pots are really designed to be board-mounted, not panel-mounted, so they have T1 LED's that are held in by silicone. It actually works pretty well.

To get each button to map to an LED, I had to build some combinational logic decoding of the triggers for each drum sound. Not hard, but a lot of wire-wrapping.

I'm not showing pics of the inside because, while the externals are pretty, the innards are NOT! ;)"