DOEPFER / A-135-2V Quad VCA / VC Mixer

Variations

The A-135-2 Quad VCA / Voltage Controller Mixer is a smaller version of the A-135-1 VC Mixer. It contains four linear VCAs (voltage control amplifiers) and a VCA-based voltage control mixer in a compact 8HP size.

Controls, inputs/outputs and functions of each VCA
Level (manual control of the amount of amplification of the VCA) : small rubber knob (L1?L4)
CV input with attenuator (CV1?CV4) : approx. 0V ? +5V CV range (with attenuator knob turned to maximum). Attenuator for attenuating high CV. Plastic shaft with white markers
Signal input
Signal output
All inputs and outputs are DC coupled, so both audio and CV can be processed using VCA. (e.g., to control the level of an LFO or envelope).
The VCA can process all signals up to 15Vpp / -7.5 to +7.5V without signal clipping. For higher levels, an external attenuator is required (e.g., A-183-1). (e.g. A-183-1)
Signals can be amplified in the range 0 to 1, with a maximum amplification of 1. (If the CV exceeds the value corresponding to amplification 1, it “clips” and stays at 1.)
“Selected” and “All” Two mixer outputs are provided
Selected output
Output of the summed signal when a plug is connected to each VCA output, except for the VCA to which the plug is connected All outputs

All output
Outputs the sum of all VCAs regardless of the plug connected to the VCA output.

The maximum amplification ratio is set at about 0.6 to avoid clipping at the mixer output. (If the maximum amplification is set above 0.6, the output will be the sum of the 15 Vpp signals from each signal input and may be distorted by the maximum amplification setting.)

CV Mixer Special Modes (selectable with internal jumper)
Dual Stereo VCA Mode
VCA1 control unit (L1 + CV1) also affects VCA3, and VCA2 control unit (L2 + CV2) also affects VCA4. Use for 2-voiced duophonic patches, etc.

Quad VCA Mode
The control unit for VCA1 (L1 + CV1) affects all four VCAs; the control units for VCA2, VCA3, and VCA4 do not operate. This mode has the same function as the A-132-2. For this reason, the A-132-2 has been discontinued. used for 4-voiced unison patches, etc.

Signal Input Normalizing Function
By setting an internal jumper, signal input 1 can be normalized to signal input 2, signal input 2 to signal input 3, and signal input 3 to signal input 4. This allows the same input signal to be distributed to four different channels by CV (e.g., audio signal distribution in the case of a quadraphonic patch, use as a CV source for the A-144 Morphing Controller or the A-143-9 Quadrature LFO, etc.). )

Width 8HP
Depth 45mm
Current consumption
+12V : 40mA
-12V : 40mA