VC Dual Amp

The ACL VC Dual Amp module comprises 2 identical fully discrete linear VCA-Bulding blocks (So it's kind of a "discrete core" module).

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 and ringing 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.