Adding a slightly odd sub-oscillator circuit to Jenny

Let’s start with some good news: Jenny‘s here to stay with me, so I can start some serious modding. The single VCO and the filter design make it hard for her to growl credibly, so I tried to make her bark and her bite a bit tougher, using bits and gates from my basement supplies: adding a sub-oscillator, and pre-filter overdrive.

Jen SX-1000 oscillator/mixer section


The sub-oscillator is simple and has been done by many great modders: You add a divider circuit to produce a one-octave (or two-octave) square-wave sub-oscillator and feed the signal to the unused “Off” terminal of the noise selector switch (over a 100k resistor so that the sub-osc signal is not overly loud). So now when the noise generators are switched off you can use the noise dial to add some deepness.

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