M800-R2extended Virtual Analog [XVA]  eurorack polyphonic synthesizer  module. Multitimbral with 4 parts. A polyphony of up to 16 voices are shared by the 4 multi-timbral parts. All of these 4 parts have their own effect stack [Mod-Delay (flanger, chorus, vibrato), Reverb, Tube-AMP, EQ, LP-Filter, DYNAMIC (Limiter) , Stereo Delay ...].

The overall audio path is stereo. That means the oscillator, mixer filter, amps and effects are all in stereo.

Four independent Arpeggiator und Step Sequenzer may play one of the four Synth parts. The Trigger Sequenzer may trigger the built in transient sample player

(Drum Kit .wav) or send trigger to the MIDI-Out or the CV outputs. Overall the sequencers/arpeggiator & trigger sequencer may managed via the clip Launcher. 

 Whats the difference in the new version (Rev2)

The Hardware:

  • The hardware is completely new designed to mainly reduce the effort to build this wonderful device
    Another reason was to expand the integration into the eurorack system (CV & GATE)
  • Hardware function keys for quicker navigation
  • Based on a powerfull Raspberry CM3+ (Quad-Core Cortex A53 1.2Ghz) industrial module
  • USB on the front panel
  • Reduced module depth (<30mm)
  • New encoder without rest (no LED ring)

The Software:

  • New XVA Synth engine
  • Has now a full stereo audio path starting from the OSCILLATORS through the stereo Filters (both A & B), through the stereo AMP (both A & B as well) and to the effect stack (every kind of effect is stereo). See Voice Structure
  • 2 x Wavetable Oscillator with spectral morph capabilities or Algorithm Oscillator as alternated oscillator function. 4 Instances for each of them
  • Noise Sample based Oscillator
  • Enhanced Mixer for better audio signal path routing
  • Now 3 LFO's
  • The M800-R2 connects with 2x CV & 2x Gate to other eurorack modules. (This can be used as Midi to CV conversion or from the built in Arpeggiator/Sequencer)
  • USB Midi Device Manager with 4 internal Ports




Width: 32HP, Height: 3HU, Depth: ~30mm

Power Consumtion 

+-/ 12V/18mA +5V/> 1.1A depends on the operating condition and connected USB devices


2x [1V/Oct] outputs 0-8V


2 x Gate signals  0-5V

Audio In/Out 

2x2 Channels maximal +-/8 V, audio rate 44100 smp/sec 24 bit


1x Midi Input Output Port (16 Midi Channels)

USB 2.0

Hot connect for USB/Ethernet, USB-Midi


Eurorack compatible 16 pin Header power connector, 6pin Header expansion bus connector (e.g M701)



Firmware OS:

The XVA-Sound Engine of the M800-R2 runs on top of a Linux OS with real time extensions. The overall boot time is < 30 sec.

All contents like wavetable-, sample-files, preset and sub-preset files are stored on the internal filesystem.

The filesystem is accessible over ethernet (USB-Lan Adapter).

Managing presets, samples, wavetables configurations & updates are possible and easy to handle.

Synthengine Structure

Configuration example:

You may connect classic midi keyboards on the MIDI-IN port (3.5mm Jack) or midi based devices (Drum Computer, Synths ...) on the MIDI-OUT. Over USB you may connect midi controllers as well. In total 4 midi USB devices can be managed by the M800-R2.

With the build in midi device manager you are able to map those USB midi devices to a certain port (4 ports for MIDI Note & CC Events). In the midi settings you may choose that port for which Midi Note-Event or CC should be processed.

With the "midi learn" you may assign the most sound forming parameter to a certain midi device, channel and control.

The internal control bus allows the expansion for additional control modules.