Schematics / Voltage Controled Amplifier
Voltage Controled Amplifier by ACX Synth ,page dedicated to this THAT 2181 based VCA http://www.acxsynth.com/VCA/vcafr.htm ,along with bill of materials and details on construction and performance .From there the brief description :
THAT the company specializes in high-end audio circuits. Among these, there is a VCA interesting is the 2180. It requires no adjustment and provides excellent performance. The dynamic range is greater than 120 dB distortion 0.0025% (model A). This circuit is however quite expensive. For this module, I simply resume the manufacturer's datasheet. My work is limited to the design of the PCB and the design of the control system voltage.
This circuit is logarithmic response which indicates that the gain in dB is linear with respect to the input voltage.