µJove VCF

Voltage-controlled filter (6HP)

Based on:
uJOVE by Plum Audio.

BOM:
interactive version

Compact version of the System 80 JOVE multimode filter designed by Plum Audio, with a custom FR-4 panel.

Build notes

To calibrate this module (I find most guides only give partial descriptions):

  1. Start in 12dB low-pass mode (orange LED) with Frequency and Resonance panel potentiometers fully closed (CCW).
  2. Feed a 50 Hz (low audio range) 10V peak-to-peak square wave into input 1, most Eurorack VCOs (or LFOs) should be able to provide this.
  3. Trim FREQ ADJ (TR1) so that the filter is fully closed (no audio makes it to the output).
  4. Switch to high-pass mode (green LED) and turn Frequency fully open (CW). Most of the high frequency harmonics should be gone, adjust TR1 if not.
  5. Go back and forth between steps 3 and 4 to get to your sweet spot between both modes.
  6. To calibrate resonance: using the same 50 Hz input and 12 dB low-pass mode from steps 1-2, set Frequency to 12 o'clock & Resonance fully closed.
  7. Trim RES ADJ (TR2) to eliminate all resonant peaks from the output - you should see a flat square wave (like the input) on an oscilloscope.