Ripples is a voltage-controlled multimode filter. It provides 3 output modes: high-pass, band-pass and low-pass. Additionally, the slope (2-pole or 4-pole) of the band-pass and low-pass outputs is switchable.
The filtering is achieved by a high-quality quad VCA. An OTA in the filter feedback path brings the resonance under voltage control, and also serves as a soft-limiter to ensure a clean self oscillation.
Finally, a VCA allows the level of the low-pass output to be modulated by a CV. This makes Ripples a good “final stage” module for a subtractive synthesis patch.
The tonal character of the filter is inspired by Japanese classics from the 80s.
- Width: 8HP
- Depth: 25mm
Power: 35mA @+12V / 35mA @-12V
A multimode filter
- High-pass, band-pass, and low-pass outputs.
- Switchable slope control for the band-pass and low-pass outputs. The slope of the high-pass output varies with resonance.
- The low-pass output goes through an internal VCA - the perfect “end of subtractive chain” output!
All the CV inputs you need
- Un-attenuated frequency CV, calibrated for 1V/Oct tracking of the self-oscillation tone over 4 octaves.
- Frequency CV with attenuverter.
- Resonance CV. Self oscillation starts at 4V. Control voltages above 5V are non-linearly compressed, for fine control of resonance overdrive.
- VCA level for the low-pass output.
- Cutoff knob range: 20Hz to 20kHz.
- Fully analog, based on the V2164 low noise/distortion quad VCA chip, and LM13700 OTA for that extra bit of non-linearity.
- Frequency CV inputs impedance: 100k.
- Audio input impedance: 100k.
- Resonance input impedance: 22k.
- VCA level input impedance: 39k.
- All CV inputs handle audio-rate modulations