Polyphonic Keyboard Controller for Eurorack Synths


 FVC - Four Voice Controller for Eurorack

5 Different Combinations 

  • FVC-1         Four Voice Controller Keyboard Logic
  • FVC-EG1    ADSR/voice  0-5V output  
  • FVC-EG1+  ADSR/voice  0-10V output
  • FVC-EG2    VCF ADSR/voice + LFO  0-5V output
  • FVC-EG2+  VCF ADSR/voice + LFO 0-10V output 
 


Features  

All functions are controlled with CC numbers so you need a controller keyboard 
5 Volt versions are suitable for Behringer Model D, Pro-1, Cat and K2
10 Volt version best for 2-XM but 5V version still a useable range

 

 FVC-1  - Basic Version

  • Polyphonic control of 4 MIDI channels.
  • Keyboard modes based on the original Oberheim FVS.
  • 2,3 or 4 voice operation.
  • MIDI IN and 2 unbuffered MIDI Outs  (TYPE A MIDI Jacks).
  • Continuous (Round Robin) or Reset.
  • Split.
  • Split Mode = Mono-L Poly-R or Poly-L  Mono-R.
  • Unison.
  • Freeze.
  • -1 /+2 Octave transpose in semitone steps per Voice - great for stacked chords
  • Faux Vibrato LFO (uses an offset via Pitch Bend message).
  • (Thanks to Mo Thunderz for the LFO Library!! ).
  • 4 Waveforms - Saw, Tri, Sin and Square.
  • Adjustable Pitch Bend and Split Point.
  • 64 Patch Memories - recalled with MIDI Program Change.
  • Split, Pitch Bend range, LFO settings and Transpose saved per patch.
Parts: Requires a Pro Micro, Opto-isolator, 3 x Stereo Mini Jacks plus some passive components. I can sell you a preprogrammed Pro Micro and instructions for £20 plus postage. You have to source the other parts yourself but I would provide a list.
You could add a 14HP panel using 4 standoffs - see the pictures below
You will also need 3 x Type A MIDI Cables (Befaco pack of 3 for £11.99 at Signal Sounds).

Please note this is not a commercial venture but  contact me if you would like to build one.

FVC-EG1/2

As above plus
ADSR envelope per channel for VCA  or VCF 
ADSR Output 0-5V
ADSR settings saved per patch
Parts: Additional 4 x Mono Mini Jacks, 4 x LEDS  plus a few passive components

FVC-EG1/2 +

As above but ADSR Output 0-10V
Parts: Additional 2 x Op Amps and some passive components required for the Voltage Doubler



FVC-EG2+

ADSR envelope per channel use for VCF 
VCF LFO with 4 waveforms
VCF Tracking
ADSR Output 0-5V
ADSR + LFO settings saved per patch

Here is photo of a complete system using standoffs so you can add a 14HP cover to each one.


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The FVC1 is all you need if you just want the Keyboard Logic and faux Vibrato
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MIDI CC List

Roland A300 Pro Parameters
B = Button  S=Slider R= Rotary L = Button


Pitch Bend Range (can be set on the fly using the sustain pedal/button)
Sustain pedal/button is used to select Split Point on the fly. 
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The basic version just needs a Pro Micro and a few components for MIDI in which can be easily mounted on the SIAM Modular prototype board. 10V versions need some op amps for voltage doubling. All power is supplied on 16 pin Eurorack header.

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