The discrete VCA circuit is a new circuit, not based on any common or classical design. It works using a entirely different principle than commonly used VCA-designs, in fact, yet we have never seen VCA´s using that principle.
This VCA circuit enables excellent technical properties like:
– very low harmonic distortion in the whole linear gain range
– no crossover-distortion due to class-A operating mode
– no overshoot´s and ringing´s due to no use of global feedback for operating point
stabilisation and linearisation, only local feedback used
– very low CV-feedtrough due to a very good common-mode rejection
– very high „offness“, so no audio-feedtrough from the input to the output
– very high dynamic range, not completely used, to provide some headroom
– very high bandwidth, completely DC-coupled signal path.
Beside the 2 individual audio outputs from each VCA, there is a Sum-output which
provides the mix of the output signals of VCA 1 and VCA 2 and of the signal coming from
the Aux-input.
The Aux-Input adds an external audio signal to the Sum at unity gain.
For each VCA there is a manual control knob for the gain as well as a Control-CV input.
The Audio and the Control-CV input of VCA 2 is normalled (normalized) to the
corresponding input of VCA 1, so if no cable is inserted in CV or/and audio input of VCA2,
the CV and/or audio signals at the CV and/or audio input of VCA 1 will be copied to VCA 2.
So it becomes very easy to create functions like VC Crossfader and VC Stereo-Panorama,
VC FX send, VC Mixer or you can just use both VCA´s individually of course
