DSP Synthesizers Revives The Oberheim OMX Drum Machine As Eurorack Module

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It started with a Behringer prototype and ended up in a compact Eurorack module, where you can find the well-known Oberheim OMX sounds!

DSP Synthesizers has recently released several interesting Eurorack modules at a very fair price. Among other things the most affordable USB-MIDI to CV interface on the market. The developer launched today a new module that revives an old drum machine from the past. RMX is a new 12HP eurorack drum module that features the iconic sounds of the Oberheim OMX drum machine. The design is based on the RMX-6 drum chip that has been around since 2016. The chip features 6 separate outputs for the drums and separate tuning.

The module features also a MIDI input 3.5mm TRS-jack type A and a USB-MIDI I/O 3.5mmm TRS-jack. It allows to transmit triggers and tune knobs to DAW over USB.

Background Story

DSP Synthesizers is a Swedish company founded in 2014 by Jan Ostman that sells preprogrammed DSP chips for the DIY market. The dsp-G1 analog modelling synth chip is also stocked by Adafruit. The chips are for inclusion in DIY projects but some are also available as open-source projects at “

  • While working on a prototype for the Behringer OMX an idea struck” says founder Jan.
  • “ This would make a great eurorack module.”, so a small sidekick began.

The design is based on the RMX-6 drum chip that has been around since 2016. The chip features 6 separate outputs for the drums and separate tuning. Besides trigger inputs it also has integrated MIDI input. A modified version of the chip, adding USB-MIDI is used in the RMX module. The chip hosts the EPROM a-Law companding drum sounds onboard so EPROM’s are not required. But it also retains the original character of the variable sample rate sound.

So the work began with designing the PCB. What could be the small lets possible rack HP space that would still host the original slider potentiometers? It was essential to have the original sliders for drum mixing. And also the drum tuning knobs available on the front panel. Using 20mm travel potentiometers the mixer just exactly fits in 12HP (61mm).
Designing with slider pots is not very common in the eurorack market. Besides the mixer the panel had to host 6 knobs for tuning. And a whopping 15 jacks. That is a lot for just a 12HP module.

While tight it all fits behind a 1.5mm screen printed aluminum panel with only 35mm depth. Not really a project for the DIY community. But the result is a great module with that vintage feel and sound of the 80’s.


  • 18 classic 80’s EPROM drum sounds (a-Law 8-bit 24KHz)
  • 6 voice polyphonic
  • 6 slider knob volume mixer
  • 6 tuning knobs 15 – 30 KHz sample frequency
  • 6 separate drum outputs
  • 1 mixed mono output
  • MIDI input 3.5mm TRS-jack type ‘B’ (Arturia)
  • USB-MIDI I/O 3.5mm TRS-jack (tip is D-)
  • Transmits triggers and tune knobs to DAW over USB

DSP Synthesizers RMX is now available for $339 USD /290€ from the official web shop

More information here: DSP Synthesizers

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