Proposed updated doc for the V2 VCV Fundamental VCA

Depending on how this is received, I may take a stab at documenting some of the other VCV modules in V2.

Fundamental VCA

A Voltage Controlled Amplifier allows the level of an audio or CV signal to be controlled by another CV signal.

A signal passing through IN to OUT is attenuated by the “LCD” slider Level with a gain ranging from 0 to 1, measured as percent (0 - 100%).

If a CV signal is patched into the unlabeled CV input, then the input is further attenuated by the control voltage. The slider Level sets the maximum gain, and the CV signal specifies the proportion of that gain to be applied. The CV is expected to be in the 0 to 10V range. A CV of 10V applies the full slider gain, while a CV of 0V mutes the signal completely. CV above 10V is clipped at 10V, and negative CV is treated the same as 0V.

Neither the IN voltage nor the OUT voltage is constrained in any way. This is only possible with a virtual synth like VCV rack. This would not be true for a hardware VCA.

The VCA formula can be expressed as out = in x (Level / 100) x (CV / 10V)

The context menu includes an “Exponential response” option. If enabled, then the VCA gives an exponential response to the CV for more exaggerated and faster envelopes.

VCA is fully polyphonic. The number of output channels is equal to the maximum number of channels fed into either the IN or CV input. The behavior of the other input depends on the number of channels presented. If one input is monophonic, then the signal will be replicated to match the number of channels in the other input. But if it is polyphonic, then missing channels will be treated as 0V.

Examples (assuming slider Level is at 100%, exponential response disabled):

        Input voltages                Resultant Voltages
    --------------------------    --------------------------
CV  3 channels:  2V,  5V, 10V     3 channels:  2V,  5V, 10V
IN  1 channel:  10V               3 channels: 10V, 10V, 10V
OUT ............................. 3 channels:  2V,  5V, 10V

CV  3 channels:  2V,  5V, 10V     3 channels:  2V,  5V, 10V
IN  2 channels: 10V,  6V          3 channels: 10V,  6V,  0V
OUT ............................. 3 channels:  2V,  3V,  0V

CV  1 channel:   5V               3 channels:  5V,  5V,  5V
IN  3 channels: 30V, -8V,  8V     3 channels: 30V, -8V,  8V
OUT ............................. 3 channels: 15V, -4V,  4V

CV: 2 channel:  12V, -5V          3 channels: 10V,  0V,  0V
IN: 3 channels: 30V,  8V, 10V     3 channels: 30V,  8V, 10V
OUT ............................. 3 channels: 30V,  0V,  0V

If VCA is bypassed, then all channels of the input are passed through unchanged.


for quoting text use

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1 Like

Perfect! I made the edit. Thanks

That’s explains a lot. Thank You!