7 things to know about Chord Organ mk1

4 HP | 40mm deep | 75mA
Designed 2017

Modular Grid | Videos
Github | Schematic

Available from Thonk

  1. It's perfectly possible to create chords on a modular synth, but its a pain - lots of tuning and messing about. I wanted to create something as simple as a home organ with chord buttons. Chord Organ is exactly that; the top knob chooses a chord shape, the bottom a root note.
  2. The full story of Chord Organ, including how it was inspired by a Bontempi Organ found in the street, is in this article over on Medium.
  3. Chord Organ and Radio Music are identical modules; you can convert one to the other by installing new firmware over USB - details on how to install the firmware - and go back just as easily.
  4. This video shows what you can do with a Chord Organ in a simple little case. Here the chord shape and root note are sequenced by an expanded Turing Machine and filtered through a God's Box Humpback Filter.
  5. The top knob chooses the chord shape (Major, Minor, Drop 3 9th). The bottom knob chooses the root note. Both can be CV controlled.
  6. The latest firmware now includes:
      A choice of 12 waveforms (the original just had four) Program chords by uploading MIDI files Easy to use configuration page. Alternative tuning support by dropping standard Scala files onto the SD card (installation details).
  7. There’s a long history of press-button-to-get-chord instruments; accordions, the Suzuki Omnichord, the Autoharp, or all those auto-accompaniment electronic keyboards that you used to see.

My first Chord Organ demo in a little lunchbox case


MylarMelodies builds a Chord Organ live


Here's Ebcidic getting deep dubby sounds from his Chord Organ


Here's Voltage Control Lab on programming custom chords into the module


Build video and demo from Synth DIY Guy