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.