Synthesis Technology E440 Discrete OTA VC Lowpass Filter
The E440 from Synthesis Technology is a low-pass VCF with three outputs, each occupying a different slope of the filter: 2 pole, 3 pole, and 4 pole. Two CV inputs control the cutoff frequency, while the third controls the resonance. The module is capable of self-oscillation at higher rates for use as a sine-wave VCO with 1V/Oct tracking and a four-octave range.
Resonance goes into tasty self-oscillation
Standard and inverting FM inputs with dedicated FM amount controls