(uVCA II) dual exp/lin VCA

This is the version II of the original µVCA.

Features:

• Continuously adjustable curve response (from linear to exponential)
• Gain trimmer (it is possible to get positive gain)
• Dedicated CV attenuators
• Leds for monitoring CV signal
• When no cable is patched to Out A, In A is normalled to Out B, offering a 2-channel mix.

This module was adapted from a design by David G. Dixon. Unlike many VCAs it closes fully (> -100dB): special circuitry has been added to bias the VCA circuitry beyond its fully closed point when the knobs are turned all the way down.