Fantastic filter.

The SVF is a 4hp 2 pole 12dB State Variable Filter Eurorack Module available as a Eurorack DIY Kit, PCB and Panel, or Built Module.

It provides Low Pass, Band Pass, and High Pass outs inspired by WASP and Thomas Henry filter topologies. The filter has 2 audio inputs, but channel 2 is jumper selectable between standard audio in or Ping-able operation. The 2019 revision also adds improved cutoff and resonance response and attenuversion through the ACV IN using the above pot. CV IN provides another unattenuated voltage input to modulate the frequency.

At the CV in, +10v will open the filter completely if the cutoff pot is CCW(counter clockwise). With the cutoff knob at noon the filter can be opened with +5v or closed with -5v. CV input at the ACV in is dependent on the CV attenuverter knob.

There are also several jumper selectable modes for max resonance, self oscillation or no oscillation based on the setting of the resonance pot.  According to the jumper configuration, the filter is capable of clinical and clean, to juicy and drippy, to low pass gate sounding plonks, to screaming chaotic resonance. When set to self oscillation mode, the filter can produce a sine like wave with no input and a trapezoid like wave in the max resonance jumper setting. In max resonance mode, the filter output can exceed 10Vpp. On the newest version, there is a trimmer on the top pcb to set the lowest cutoff frequency. With resonance at 0(fully CCW) and with the frequency up the filter will self oscillate in some modes/situations.

The new black and white pcb/panel is reversible meaning, one side is classic(first picture) and the other side is soulless(second picture). Black/Red panels are currently discontinued.

Version 7 released in 2026 is now expandable and easier to solder with resistor arrays replacing many of the single resistors. And now the low and high frequency thresholds can be fine tuned with trimmers on the top pcb.

• Width: 4hp
• Panel Material: PCB
• Reverse power protected
• Current Consumption: +12v: 15mA max, -12v: 15mA max
• Depth: 46mm
• Ships with M3 black nylon screws
• Build Difficulty: Intermediate
• Expandable: v666 no, v7 yes