Voltage Controlled Amplifier Diy

0v cv into the vca will cause it to fully attenuate i e 80dbv.

Voltage controlled amplifier diy. A voltage controlled amplifier vca has two kinds of inputs. One option to build your own is a jfet junction field effect transistor based voltage controlled amplifier. Voltage controlled amplifiers or vcas are a common component in modular synthesizers. Since the traditional use of a vca is to turn down a signal until control voltage is applied max cv into a vca will set the amplifier to unity gain or 0dbv no gain.

Incrementally lower voltages turn the jfet on more lowering it s resistance. Voltage controlled amplifier vca by scott rise. A vca or voltage controlled amplifier lets you use a voltage to control the amount of another signal that is allowed through to the output of the module. Changing the voltage on the power supply is not a good idea because the op amp needs a specific and constant power supply to function we are only in possession of one variable dc voltage supplier.

They re basically a volume control that can be set using a reference voltage. The higher the control voltage the more signal is passed. With a p channel jfet you apply a positive voltage to turn it off. In a modular synth their primary job is make notes start and end the volume is to raise when a key is pressed and it s told to lower again when a key is released.

Carrier signal input this is the input where a bipolar signal comes in. Effectively most vcas are actually voltage controlled attenuators.