The Quantus Ampla by Noise Engineering is a compact quad VCA with a few finesses. Each channel can be set via a toggle switch to behave normally, i.e. to let more of the signal through as the voltage increases, or to have the control voltage close the then open VCA. The latter is ideal for ducking effects and can be used as a downward expander. Since the CV inputs and signal outputs are normalized, combinations are also possible: If audio signals are present at the first three channels and an envelope is applied to channel 1, the sum processed by the envelope is present at output 3. This leaves channel 4 free to control the intensity of an LFO with Velocity . Quantus Ampla is DC coupled and therefore equally suitable for processing audio and CV signals.