CubuSynth Dual CS-20

CubuSynth Dual CS-20 VCF: Two screaming MS-20 filters in one module


The Dual CS-20 stuffs two Korg MS-20-style filters into a single module and makes them sing, phase and behave badly while glowing a delightful green.

Dual CS-20

The CS-20 looks far too stylish to emulate the rough-as-anything MS-20 filter, but it does so twice. The Dual CS-20 has two 12dB/Oct filter cores with independent and intertwined features. While you can control each filter via CV the manual controls are tied to both pushing you to play in stereo with a pair of filters.

However, CubuSynth are keen for you to experience the self-oscillation from the overblown resonance circuits and treats you to a green glow around the cutoff in celebration of its transformation into an oscillator. With two oscillating cores you can have all sorts of fun with phasing and cross FM modulation.

The sound coming from the demo video is deliciously raw. When they crank up the resonance over a sawtooth input there’s definitely a lot of MS-20 grit going on. The HP/LP morphing is nice and gives you a great range of timbres. If you go straight to oscillations, then the 1v/Oct input will give you good tracking over a couple of octaves. I like how a mild modulation to the resonance can send it just to the edge of chaos before pulling it back. Nice.

I’ve not really got into stereo in my modular yet – only with effects I suppose. So that’s another avenue to explore and the Dual CS-20 looks like a very cool and compact way of doubling up on those filtered audio signals. It’s very reasonably priced too at £173.