The Eternal spring filter is quite different to most filters we’ve tried. It belongs to that category of sound modifiers which are usually called “effects”, which is to say that it doesn’t just filter the sound in a regular manner, but also adds a considerable amount of character and personality. Depending on its drive and Resonance (Q) settings, the circuit can add a little bit of saturation or heavy distortion to incoming audio material, sometimes even sounding like a Wavefolder. This filter sounds great on synth leads and bass lines, and really adds a lot of movement to drones. In addition to cut-off and Q controls, there is a CV input with attenuator and a phase inverted FM input. Drive and Q parameters will influence each other and the lack of temperature compensation can cause musical instabilities!
Features:
- Drive control for adding soft saturation and harmonics
- CV input with depth control
- FM input with inverted response for wild audio rate modulation
- Playable Q knob
- Unique waveshaping capabilities
- Self-oscillation that mixes nicely with the incoming signal and doesn’t squeal
- No temperature compensation/simple expo translates into a signal that constantly “moves”
- Multiple gain stages act as a natural limiter
- Ability to turn your sines and triangles into intense acidic basslines
Eternal Spring Filter – Manual | Build Document
Specs: Width – 8HP | Current Draw – 10mA