This module offers a VCF based on the popular CMOS-based Wasp VCF and, in addition, features adjustable post filter distortion.
A little on how it works: Of note is that the filter core is running between 0V and -5V, allowing a simple exponential converter to be used to give an appropriate response to the control voltage. The distortion channel and straight signal are mixed via a seque circuit (reverse panner). The final stage is just a regular, inverting amplifier, but with a voltage divider in the feedback loop to avoid the need for an excessively high value resistor to achieve the required gain.
|Additional Resources||Build Guide