3 - THE VCA (Voltage Controlled Amplifier) :
A module that allows you to let the incoming signal pass only when you want, using an external signal from another module (LFO, Envelope, Clock signal … for example).
IN : jack input for your incoming signal
CV : CV IN jack for the incoming external source (from another module) which will open the VCA (more or less and more or less long depending on the signal) to let the signal through.
CV ATTENUATOR : a pot to adjust the level of your CV in.
Exemple of a simple patch with this 3 modules (VCO + VCF + VCA) +1 for triggering the VCA :
OUT of the VCO to INPUT of the VCF, OUT of the VCF to INPUT of the VCA, OUT of the VCA to your system
- one LFO or ENVELOPE or SQUARE WAVE … OUT to the CV IN of the VCA for triggering it, and now the VCO sound is no longer continuous
if you can multiply the trigger source (with a Multiple), or use another source different from the first (another LFO, Envelope …), you can also act on the CV of the filter.