Five-pole near-elliptic low-pass filter

Synthesizer VCF with a unique circuit topology and extremely sharp cutoff (61dB/octave at the shallowest part of the main slope). Built-in VCA, exponential and linear modulation, temperature-compensated V/oct tracking. Functions as a sine wave VCO in feedback mode.

https://northcoastsynthesis.com/products/msk-007-leapfrog-vcf