LPG / LPF Passive Vactrol Module

Passive Vactrol LPG / LPF Low Pass Filter, Modular Synth Eurorack

This compact module combines a Low Pass Filter (LPF) and Low Pass Gate (LPG) in a simple passive design using a vactrol response for smooth, organic filtering and natural decay characteristics. Ideal for adding warm, percussive tones and classic “woody” LPG behaviour to modular patches.

Selectable operating modes allow use as:

– Low Pass Filter (LPF)
– Low Pass Gate (LPG)
– Bypass

The vactrol-based circuit gives a soft, musical response that works especially well with plucks, percussion, drones, and experimental patches.

Specifications:

– Passive (vactrol-based) design
– CV / Gate input
– Audio input
– Audio output
– Cutoff control
– Mode switch: LPF / LPG / Bypass
– 3.5mm jacks (Eurorack compatible)
– 6HP Eurorack Plate (available separately)

Measurements:

– 46mm x 74mm x 23mm
– 4 x 2mm mount holes

About Vactrols

A vactrol is an optoelectronic component combining an LED and a light-dependent resistor (LDR) in a sealed housing. As the LED brightness changes, the resistance changes smoothly, creating the characteristic warm, natural, and slightly slow response highly valued in many classic LPG designs.