12 HP
Current Draw
13 mA +12V
25 mA -12V
? mA 5V

Module is available as a DIY project only.

This Module is currently available.

La cigale - 1J17b or 1J24b Tube VCA and vactrol VCF

Tube VCA, LP / HP filter

Dual vactrol Sallen Key VCF/VCA with tube distortion. Switchable between low pass and high pass.

Soundpath :
Input-1 --> attenuator 1
Input-2 --> attenuvertor 2. If nothing is plugged in Input-2, the output is fed in attenuvertor 2 for feedback control.

Mix of output of attenuator 1 + attenuvertor 2 goes to the VCF

VCF has two control Freq CV + Freq Pot. A switch can choose between low pass and High pass by changing the vactrol wiring. Note that with the second attenuverter providing feedback the output may have two resonant peaks at different frequencies . This can lead to cool or strange results !

VCF output is fed to the tube wich act has VCA.
VCA has two control Gain CV and Gain Pot. Audio can be fed in the Gain CV for more fun.
Tube bias can be choose between "hot and cold".

Resonance control is changed by... the Res Pot. The filter will need an input to self-resonate.

When adding feedback + resonance, the output may produce some nice chirp sounds. Hence the "Cigale" design (cicada). For some it will be annoying, personnaly I love it.

Insprired by ken stone design of the CG65 and mods by primate synthesis with suggestion by Scott Ryan Williams and scott Stities.

1J17b and 1J24b soviet tubes can be used. 1J17b has a 60mA -12v consumption where 1J24b has 25mA. Their characters are a bit different.

Happy User Review :

Feel like adding a little organic sound to your synth ?
Or even a bit of unexpected sound ?
Put on a tube!

I love this module, it's well thought out, and there are many ways to vary the sound that runs through it.
It's easy to make, but it shouldn't be your first DIY module.
Nice :D


Ø 5.00 (1 Votes) Average Rating
submitted Aug 26th 2023, 13:09 by kroubikou | last Change Apr 3rd, 09:08 by DubHalley
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