Kilpatrick Audio K3021 Master VCO Module Now Available

Kilpatrick Audio shared this video demo of their new K3021 Master VCO Eurorack module.

The K3021 Master VCO offers a single channel oscillator, based on the K3020 Dual VCO design. The K3021 uses a new triangle core design, though, based around discrete transistors for stability.

One of the features that makes the K3021 special is its use of complex waveshapers and pulse width modulation circuits to create unique timbres. You can select between sine, triangle and ramp waveforms for the WAVE section. These waves then feed into the triple pulse width modulator to create very rich pulse waves that have a much more lively character than a simple single-channel PWM. Choose from one of three PULSE output combinations for unique variations.

The BLEND and PULSE outputs can be used independently, or can be combined through the use of the ultra-low distortion blend section. Smoothly fade between the WAVE and PULSE waveforms either manually or with voltage control. By using the blend circuit especially with the LFO mode engaged, very complex modulation waveforms can be easily created.


  • Eurorack (3U) form factor – 18HP width
  • Master VCO with on board precision power regulation
  • LED indication of selected switch positions and VCO core activity
  • 1V/octave CV input – factory trimmed for 1V/octave response
  • Linear FM input with level control
  • Fine and coarse tuning controls
  • Normal VCO frequency range: 2Hz to 15kHz
  • LFO mode switch – period approx. 60 seconds to low audio range
  • Temperature compensated exponential converter with matched transistors
  • All-new discrete triangle-core and sine wave shaper
  • Wave shaper with sine, triangle or ramp waveforms – switch selectable
  • Pulse shaper with triple pulse width modulators for complete timbres
  • Voltage controlled mixing between wave and pulse waveforms
  • High-end blend VCAs with ultra-low distortion and linear control
  • Sync input for hard syncing of VCO core
  • PWM input with level and offset controls
  • Blend VCA control input with level and offset controls – full deflection with 5Vpk-pk
  • Blend output – output from the blend VCA containing wave and/or pulse waveforms
  • Pulse output – dedicated output from the pulse shaper containing pulse waveform
  • All inputs and outputs are tolerant of +/-12V
  • All outputs drive 10Vp-p with 1K output impedance

Pricing and Availability

The Kilpatrick Audio K3021 Master VCO Eurorack module is available now for US $325.

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