Doepfer - A-135-1: Voltage Controlled Mixer / Quad VCA
Module a-135-1 is a quad voltage controlled mixer. it is made of 4 independent linear vca's. the vca outputs are mixed to a common output. for each vca the following inputs and controls are available: audio input with attenuator, control voltage input with attenuator, gain (pre-amplification). the vca's are realized with high-quality cem vca's (cem3381 for version 1 and ssm2164 for version 2).
applications: voltage controlled mixing of up to 4 audio signals with separate control voltages (e.g. delivered by lfo's, adsr's, random, shepard generator, midi-to-cv interface or other control voltage sources). in connection with the morphing-controller a-144 the soft fade-over of 4 audio signals with only one control voltage is possible.
inputs: 4 x signal in, 4 x cv in
output: signal out, version 2 in addition: 4 x single out
controls: 4 x signal in attenuator, 4 x cv attenuator, 4 x initial gain
the first version of the a-135-1 was able to process audio signals only because the signal in/outputs were ac coupled. the first version cannot be used to process slowly varying control voltages! it has been manufactured until about april 2013 and can be identified by the missing single outputs, the 22 hp front panel width and the vca circuits (cem3381 or pa381)
the new version of the a-135-1 is able to process also slowly varying control voltages because the signal in/outputs are dc coupled. it has in addition four single outputs available and can be used as four independent linear vcas. the new version is manufactured since may 2013 and can be identified by the additional four single outputs, the 18 hp front panel width and the vca circuits (ssm2164 or v2164)
it is not possible to modify version 1 for dc signal coupling or single outputs !