Doepfer

Notes: Module A-134-2 contains two identical voltage controlled crossfader units.

Each unit has two voltage controlled amplifiers (VCAs) with opposite control behaviour available. The outputs of the two VCAs are mixed together to obtain a common output. The behaviour of the control voltage inputs can be chosen with an internal jumper:

Symmetrical mode: If the corresponding jumper is not set both VCAs of the crossfader have the same 50% amplification with zero CV. If the applied CV becomes positive the amplification of VCA1 decreases and those of VCA2 increases in the same way. A negative CV has the opposite result. The CV voltage range to obtain the maximum/minimum positions of the crossfader is about -2.5....+2.5V. This mode is useful for bidirectional (i.e. positive and negative) control voltages, for example LFO or joy stick (adjusted to 0V CV in centre position).

Asymmetrical mode: If the corresponding jumper is set VCA2 is fully closed and VCA1 has full 100% amplification with zero CV. If the applied CV becomes positive the amplification of VCA1 decreases and those of VCA2 increases in the same way. The CV voltage range to obtain the maximum/minimum positions of the crossfader is about 0...+5V. A negative CV has no function in this mode. This mode is useful for unidirectional (i.e. only positive) control voltages, for example ADSR, ribbon controller or Theremin control voltage.

The CV input of the upper unit (CV1) is normalled to the CV input of the lower unit (CV2). I.e. if no plug is inserted to CV2 the CV input of the upper unit (CV1) also controls the lower unit.

The second signal input of the upper unit (In1B) is normalled to the first signal input of the lower unit (In2A). I.e. if no plug is inserted into In2A the signal In1B is used as the first signal input of the second unit.

As the inputs and outputs are DC coupled the module can be used for both audio and control voltage signal processing.

Notes: The A-138d primarily is used for crossfading between two modular signals. On the other hand you can used it for inserting stompboxes or other effects into your modular system. Both the inputs and the mix output are available twice, like a mini-multiples e.g. for using the input signal also for other applications, kind of like a Thru.

Crossfader: With the crossfading control CF you blend manually between the inputs In 1 and In 2. The Mute switch allows for muting one of the two signals, independent on the crossfader position.

Effect insert: The signal at input In1 is emitted at the FX Send output and can be attenuated with the Atten. control because the modular system works with much higher levels.

The effect unit's output is inserted to the FX Return input socket and its level can be boosted with the Amp. control. The processed signal is available at the bottom in 2 socket.

Use the CF control to blend between the original signal and the effect signal and to mute switch for quick muting e.g. of the effect return signal.

Notes: 2HP narrow version of the A-180 multiples module. It is a passive signal splitter suitable for audio or CVs. Two sets of four jacks are interconnected, by placing a solder bridge you can connect all eight jacks.

Dimensions
2 HP
18 mm deep

Current Draw
Module does not draw current

Notes: Module A-185-2 is a precision control voltage adder/buffer. Precision means that the amplification of the inputs without attenuators is exactly 1.00 and is suitable to add control voltages for the pitch control of VCOs (e.g. from keyboard + sequencer 1 + sequencer 2). Summing resistors matched to 0.1% are used to obtain an accuracy of 0.1% for the added voltages.

The module is equipped with four CV inputs: one with attenuator and three without attenuator. Each input is normalled to +1 V (i.e. if no plug is inserted the input contributes 1 V to the sum appearing at the output).

The input with attenuator can be used for common modulations (e.g. from an LFO, ADSR, Theremin, Pitch-Bender) for all VCOs connected to the output. The Lev.1 control is used to adjust the depth of the modulation, the first switch selects the polarity of the modulation. If no signal is connected to the first socket the attenuator works as a (fine) tuning knob because a voltage in the range 0...+1V (right position of the switch) or 0...-1V (left position of the switch) is added to the CV output.

The inputs without attenuators are planned to add control voltages coming out of keyboards, sequencers, Midi-to-CV interfaces, ribbon controllers or other CV sources that follow the 1V/oct standard. For example the CV of a keyboard can be used to transpose the CV coming from a sequencer, or the CV of a slow sequencer can be used to transpose the CV from a fast sequencer.

Each input is equipped with a three-position switch that determines if the corresponding voltage is added (right position), subtracted (left position) or if the input has no effect (centre position). If no plug is inserted the corresponding switch works as an octave switch for the lower three sections as the default 1 V are added or subtracted to the output voltage according to the switch position. The first switch can be used to add a variable voltage to the sum output. The variable voltage is adjusted with the Lev.1 control and the knob works then as kind of a (fine) tuning control.

The module is equipped with 4 outputs: three non-inverting and one inverting ouput. An internal jumper can be used to connect the non-inverted or inverted output to the CV line of the A-100 bus. That way the module can used to control several VCOs that are connected to the same bus board as the A-185-2 (same functionality as A-185-1).

Notes: Module A-185-2 is a precision control voltage adder/buffer. Precision means that the amplification of the inputs without attenuators is exactly 1.00 and is suitable to add control voltages for the pitch control of VCOs (e.g. from keyboard + sequencer 1 + sequencer 2). Summing resistors matched to 0.1% are used to obtain an accuracy of 0.1% for the added voltages.

The module is equipped with four CV inputs: one with attenuator and three without attenuator. Each input is normalled to +1 V (i.e. if no plug is inserted the input contributes 1 V to the sum appearing at the output).

The input with attenuator can be used for common modulations (e.g. from an LFO, ADSR, Theremin, Pitch-Bender) for all VCOs connected to the output. The Lev.1 control is used to adjust the depth of the modulation, the first switch selects the polarity of the modulation. If no signal is connected to the first socket the attenuator works as a (fine) tuning knob because a voltage in the range 0...+1V (right position of the switch) or 0...-1V (left position of the switch) is added to the CV output.

The inputs without attenuators are planned to add control voltages coming out of keyboards, sequencers, Midi-to-CV interfaces, ribbon controllers or other CV sources that follow the 1V/oct standard. For example the CV of a keyboard can be used to transpose the CV coming from a sequencer, or the CV of a slow sequencer can be used to transpose the CV from a fast sequencer.

Each input is equipped with a three-position switch that determines if the corresponding voltage is added (right position), subtracted (left position) or if the input has no effect (centre position). If no plug is inserted the corresponding switch works as an octave switch for the lower three sections as the default 1 V are added or subtracted to the output voltage according to the switch position. The first switch can be used to add a variable voltage to the sum output. The variable voltage is adjusted with the Lev.1 control and the knob works then as kind of a (fine) tuning control.

The module is equipped with 4 outputs: three non-inverting and one inverting ouput. An internal jumper can be used to connect the non-inverted or inverted output to the CV line of the A-100 bus. That way the module can used to control several VCOs that are connected to the same bus board as the A-185-2 (same functionality as A-185-1).