Skip to content

filter

Interface

  1. signal input
  2. cutoff modulation input
  3. signal output
  4. highpass/lowpass mode switch
  5. CV modulation depth (attenuverter)
  6. resonance control
  7. cutoff frequency control

A voltage-controlled filter based on a diode ladder topology. Filters shape the harmonic content of a signal by attenuating frequencies above or below a certain point.

Filter modes

The HP/LP switch selects between two modes:

Lowpass (LP) — frequencies below the cutoff pass through, higher frequencies are attenuated. This removes brightness and harshness, creating warmer, darker tones. The classic subtractive synthesis sound.

Highpass (HP) — frequencies above the cutoff pass through, lower frequencies are attenuated. This thins out the sound, removing bass and body while keeping the higher harmonics.

Cutoff

The cutoff frequency determines where the filter starts working. In lowpass mode, everything above this frequency gets quieter; in highpass mode, everything below gets quieter. The cutoff knob sweeps this frequency across the audible range.

Resonance

The resonance control adds emphasis at the cutoff frequency by feeding some of the filter's output back into its input. At low settings it adds a subtle peak, making the cutoff point more pronounced. Higher resonance creates a sharper, more aggressive peak that can make the filter "sing" or even self-oscillate at extreme settings.

CV modulation

The CV input allows external control of the cutoff frequency — connect an envelope for dynamic filter sweeps, an LFO for wobble effects, or a keyboard CV for tracking pitch.

The depth knob is an attenuverter that controls how much the CV affects the cutoff and in which direction. Center position = no modulation. Turn right for positive modulation (CV increases cutoff), turn left for inverted modulation (CV decreases cutoff).

Power consumption

540 mW