RFE

Equalizer/resonator/triple filter

There are a lot of ways to use RFE. Besides EQ and triple multymode filter, it can be a powerful sound source with FM posibilities. Use it like drone machine or triple VCO (it tracks about 4-5 octaves) or even a drum machine, it pings very well!

3 parametric sections with cv control of frequency, bandwidth and level;
3 analog filters with mode switch and mute push button;
simultaneous VCF sum and EQ outputs;
voltage control feedback.

https://twangmodular.com/product/rfe/