Drumulator 8 Kits + MIDI Board

Introduction

ROM switcher boards and third-party sound ROMs are nothing new as far as the E-mu Drumulator is concerned – in fact both were available while the machine was current. JL Cooper Electronics and others made 3-kit boards, and Digidesign (who later became Avid) got their start producing alternative sound ROMs for the Drumulator under their original name of Digidrums. That said, while the various alternative ROM sets are easy to come by these days, ROM switcher boards are not, and without one it’s a total pain to keep swapping chips in and out as you have to take out 8 screws on the underneath of the thing, lift off the lid, swap 5 chips over and put it all back together again.

8 Kits

I wanted a modification very much in the same style as my TR-707 ROM expansion board, with a number of kits that you can instantly switch between. As with that project, this is done without the need for any additional switches and instead uses a microcontroller to snoop on the front panel switch matrix. Kits are selected by holding down one of the bottom row of buttons marked 1-8 and pressing the ENTER button. The selection is remembered when the Drumulator is powered off too.

The Drumulator’s sounds are stored across 4x 16kB ROM chips, although they form one continuous region of memory. Thanks to this, and due to the way that they’re selected, it’s really easy to replace all four with a single large capacity chip. The 512kB flash ROM that I used can hold 8 kits worth of sounds, which works out nicely as that’s the stock sounds plus 7 of the Digidrums kits, including the famous Rock Drums kit:

  1. Stock kit
  2. Digidrums Alternate Drum Set 1
  3. Digidrums Electronic Drums 1
  4. Digidrums Electronic Drums 2
  5. Digidrums Rock Drums
  6. Digidrums Jazz Drums
  7. Digidrums Latin Percussion
  8. Digidrums African + Misc Percussion

Because each kit also has a corresponding modified program ROM (as the length of sounds, locations in memory and channel assignments are all hard-coded into the Drumulator’s firmware); the D8KM board also has an EPROM which contains the relevant OS for all 8 kits, and is connected to the Drumulator’s OS ROM socket with a ribbon cable. Fortunately the Drumulator doesn’t care if the OS ROM changes while the machine is running as long as they’re all the same version, which they are – ‘P3.00’, the final version.

MIDI

I chose also to include MIDI functionality as part of the upgrade, as most Drumulators don’t have it. E-mu did offer a retrofit, which has been cloned over the years, but it’s very basic and only does MIDI notes. The D8KM board on the other hand also offers the ability to sync the sequencer to incoming MIDI clock. Just set the Drumulator to external clock and if MIDI clock is available, it will automatically override the external clock signal and will also start and stop playback. If MIDI clock is not available the Drumulator will use the external clock signal as normal, including for the tape loading functionality.

Downloads

Photos