The Oakley Classic VCA
This is a vintage voltage controlled amplifier design. It is based on the classic ARP4019 sub-
module which was used on the wooden case ARP2600P semi-modular synthesiser. The design
has a fully discrete core but uses a single high quality audio op-amp for output amplification.
The unit features both linear and exponential control voltage (CV) inputs. Both can be used
together or individually.
Two signal inputs are provided, one DC coupled and the other AC coupled. The former
allows audio and low frequency signals to be processed. While the latter provides a DC block
to process only alternating frequencies. Both inputs can be used simultaneously and each one
features an input level control.
A gain control is also available to provide a fixed bias to set the initial gain of the VCA. This
way a negatively going CV can reduce the overall gain of the VCA. The gain pot can also be
used a volume control.
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