DOEPFER / A-185-2V Precision CV Adder / Bus Access

Variations

DOEPFER Eurorack modular synthesizer CV Addr/Buffer. Vintage style with a black panel.

The A-185-2 Precision CV Adder is a high-precision CV adder/buffer. With an amplification of exactly 1.00 without the attenuator, it's suitable for adding CV for pitch control of VCOs (e.g., keyboard + sequencer 1 + sequencer 2). A 0.1% matched summing resistor is used to achieve 0.1% accuracy for the added CV.

This module features four CV inputs: one with an attenuator and the other three without. Each input is normalized to +1V. If no plug is connected to an input, 1V is added to the output.

The input with the attenuator can be used for general modulation (LFO, ADSR, theremin, pitch bend, etc.) of all VCOs connected to the output. The Lev.1 control is used to adjust the depth of the modulation, and the first switch selects the modulation polarity. When no signal is connected to the first socket, the attenuator functions as a fine-tuning knob. 0 to +1V (right side of switch) or 0 to -1V (left side of switch) is added to the CV output.

Inputs without an attenuator can add CV from a keyboard, sequencer, MIDI to CV interface, ribbon controller, or 1V/octave CV source. For example, you can use the CV from a keyboard to transpose the CV from a sequencer, or use the CV from a slow sequencer to transpose the CV from a fast sequencer.

Each input is equipped with a 3-position switch that determines whether the corresponding CV is added (right side of switch), subtracted (left side of switch), or has no effect (center side of switch). When no plug is connected, the output voltage is defaulted to 1V depending on the switch position, so the corresponding switch functions as an octave switch for the three sections below. The first switch can be used to add a variable CV to the total output. The variable CV is adjusted by the Lev.1 control, and the knob functions as a fine-tuning control.

This module has a total of four outputs: three non-inverting and one inverting output. To connect the non-inverting or inverting output to the A-100 bus CV line, use the internal jumper. This allows the A-185-2 to control multiple VCOs connected to the same bus board. (This is the same functionality as the A-185-1.)

There is a pin header with three pins (labeled JP5) near the bus cable connector. Without the jumper installed, the A-185-2 output will not be connected to the A-100 bus CV line. Connecting the jumper to the lower position connects the A-185-2's CV to the A-100 bus CV line. Connecting it to the upper position connects the A-185-2's inverted CV to the A-100 bus CV line.

Width: 6HP
Depth: 50mm
Current Consumption
+12V: 10mA
-12V: 10mA