Modules A-130 and A-131 are voltage-controlled amplifiers
An exponential VCA (A-131) is usually used for audio applications, whilst a linear VCA (A-130) is used for control applications. However, this is not a strict requirement
The gain of the VCA is determined by the control voltages at the CV inputs and the position of the gain control, which sets the VCA’s base gain. Each VCA has two audio inputs with upstream attenuators; the sum of these signals is amplified in accordance with the control voltages and the position of the gain control
Note: The new versions of the A-130/131 (with CA3080) are also suitable for processing slowly varying control signals (DC-coupled inputs/outputs)
The older versions of the A-130/131 (with CEM3381/CEM3382) are not suitable for processing slowly varying control signals (AC-coupled inputs/outputs)
Flame Sidechainer
Behringer Four Play
Doepfer A-130-2 Dual linear/exponential VCA Vintage Edition
Eowave 1U Levers
Doepfer A-130-2 Dual linear/exponential VCA Slim Line