Serious Filter

A VCF after the ARP 4023, one of the two most common filter designs around with the ladder: very wide ranging, from sub-audio to frequencies only dogs can hear, and happy to self-oscillate when RES is cranked; around 8 or 9 it gives a nice sine wave, much higher and the signal clips. It shakes the room or screams like nails on a chalkboard, and makes a nice quadrature oscillator too. IN 1 and CV 1 have their attenuators, IN 2 and CV 2 none; band-pass and low-pass outputs.

Key features

• IN 1, IN 2, CV 1 and CV 2 in; OUT BP and OUT LP
• IN 1, FREQ, CV 1 and RES knobs
• 8 HP; Nonlinearcircuits publishes no current draw, depth or assembled price (it sells the DIY PCB and panel), and ModularGrid lists none