I Can't Believe It's Not a VCO

A VCF with a filter exciter, after Electronotes #132: it takes pinging a low-pass gate or ringing a filter a step further, its decaying sound fed back to its input through a VCA driven by a gate, an envelope or both, for acoustic, semi-acoustic and quite unacoustic sounds. In VCF mode, an audio signal patched into VCF switches the exciter out.

Key features

• FREQ, FINE and CV, with 1V/O and CV inputs
• ATT/VCF, DECAY/Q and RESPONSE
• ENV and GATE inputs for the exciter's VCA; VCF, the filter's own input
• Three outputs: BAND and LOW, near sines, and OUT, waveshaped
• 8 HP; Nonlinearcircuits publishes no current draw, depth or assembled price (it sells the DIY PCB and panel), and ModularGrid lists none