Rando Chordo PCB

The Rando Chordo is a specialized quantizer that takes a single CV input and outputs 4 voice CV to create chords. The chords are generated randomly and it has controls over the range of the chord (how far from the root note another note in the chord can be), the musical mode used in quantization, forcing a 5th, allowing inversions, setting whether quantization happens per note or per chord and a sample input to control when the input CV gets sampled. There's a built in tune-mode to help tune your VCOs together.

This is for a PCB (including programmed microcontroller) only suitable for multiple formats.

Availability: In stock




The Rando-Chordo is a module which takes a single CV input and then applies multiple randomly selected offsets to this voltage, quantizes the input and the offset voltages, creating 4 notes of CV from a single input. It features the following controls/inputs/outputs.


  • MODE. This knob selects what musical mode to quantize to. The chart on the right illustrates the modes, in order of most counter clockwise knob position to most clockwise.
  • RANGE. This knob limits the range of the offsets. At it's most clockwise position offsets can be as far as 2.5volts (two and a half octaves) away from the input voltage. At it's most counter-clockwise, there is no offset.
  • AUXCV. This knob controls how much of the auxiliary CV is used to modify the main CV input. When no external CV is inputted, it will act as a manual offset to the CV input.
  • NEW. This is the only pushbutton control. It causes a new set of offsets to be generated.
  • TUNE. This sets all the outputs to 1V. This allows you to tune all of your oscillators to the same note.
  • 5THs. This switch sets output #2 to always play a fifth above output #1, ignoring both the normal voltage offset and what mode you are quantized to.
  • INVERSIONS. This switch allows for negative offsets to be applied, creating inverted chords where the root note is no longer the lowest note heard.
  • QUANT BEFORE OFF. This control sets it so that the input voltage is quantized before the other offsets are applied. The result of this is that all notes in a chord will change at once.


  • CV IN. This is the main CV input. It should be between 0 and 5volts, but an offset can be applied by the AUXCV knob when not using the auxiliary CV.
  • AUX CV IN. This is an input for the auxiliary CV.
  • SAMPLE IN. A trigger can be input here to get a sample-and-hold type effect on the input CV, or a gate can be input for a track-and-hold effect. This is useful when using rapidly moving CV sources. When nothing is plugged in, it continually samples the input voltage.
  • NEW IN. A trigger or gate on this input causes a new set of offsets to be generated.


  • OUT 1. This is a quantized version of the input CV.
  • OUT 2-4. These are outputs of quantized offsetted input CV.

Quantization Modes.

  • Chromatic. All 12 semitones.
  • Major. 1st, 3rd, 5th, 6th, 8th, 10th and 12th
  • Minor. 1st, 3rd, 4th, 6th, 8th, 9th and 11th
  • Whole. 1st, 3rd, 5th, 7th, 9th and 11th
  • Major 7th chord. 1st, 5th, 8th and 12th
  • Major Pentatonic. 1st, 3rd, 5th, 8th and 10th
  • Octave and 5th. 1st and 8th
  • Octave. 1st

Specs & Downloads

Specs & Downloads

100 Barton
Depth No
+12V No
-12V No
+5V No
Additional Resources Build Guide


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