Doepfer

Notes: A-100SSB is a combination of power supply and bus board with 8 connectors for A-100 modules, planned for applications with up to 8 modules and a max. current of 380 mA.

- Wide range mains voltage input 100-240V AC / 50-60 Hz
- IEC inlet on board for the connection of a suitable mains cable (a suitable mains cable has to be purchased by the customer locally, it's not included with the A-100SSB)
- Switching supply with +12V/380 mA and -12V/380mA for the operation of A-100 modules up to 380 mA total supply current
- Safety cover at the bottom side (covers all elements that lead mains voltage)
- On board fuse
- 8 bus connectors
- LED displays for +12V, -12V and +5V
- Dimensions: about 270 mm (length) x 55 mm (width) x 35 mm (height)
- Several 3mm holes for mounting the unit on a rear panel or bottom plate

Notes: High quality rotary knob, for use with Doepfer or a wide range of modules. Robust design with indented edges. Green finish.

Notes: High quality rotary knob, for use with Doepfer or a wide range of modules. Robust design with indented edges. Grey finish.

Notes: High quality rotary knob, for use with Doepfer or a wide range of modules. Robust design with indented edges. Red finish.

Notes: High quality rotary knob, for use with Doepfer or a wide range of modules. Robust design with indented edges. Yellow finish.

Notes: High quality rotary knob, for use with Doepfer or a wide range of modules. Robust design with indented edges. Retro style finish.

Notes: Blank panel, 1HP, constructed from anodised aluminium, silver.

Notes: Blank panel, 1.5 HP, constructed from anodised aluminium, silver.

Notes: Blank panel, 2HP, constructed from anodised aluminium, silver.

Notes: Blank panel, 4HP, constructed from anodised aluminium, silver.

Notes: Blank panel, 42HP, constructed from anodised aluminium, silver.

Notes: Blank panel, 4HP, constructed from anodised aluminium, black.

Notes: Blank panel, 8HP, constructed from anodised aluminium, silver.

Notes: Bus board to connect 14 modules

An assembled and tested bus board, 22 sockets, e.g. for customers who want to built their own case and need a bus board for A-100 modules, includes cables for connection to +/-12V power supply (4 wires with flat connectors on both ends, length about 30cm), but no mechanical parts (e.g. screws, spacers, nuts, washers).

In the new version of the A-100 bus board (labeled Version 6 / 2019) boxed pin headers are used which are equipped with a reverse protection (gap for the "nose" of the socket of the bus cable). When the bus cable coming from the module is connected to the boxed header in question the "nose" has to point to the right. The polarity of the cable is correct if the red wire of the bus cable then points to the bottom (to the continuous line labeled"RED WIRE" on the pc board). If this is not the case please do not connect the module to the bus board ! Otherwise both the module and the power supply (A-100PSU3) may be damaged ! In that case please contact the manufacturer of the module and ask for a suitable bus cable with the correct polarity of the connector.

The bus cables of original A-100 modules manufactured by Doepfer are equipped with suitable bus cables since 2012. Only for older A-100 modules manufactured before 2012 it may happen that the polarity of the 16 pin female connector of the bus cable is wrong (nose points to the left when red wire points to the bottom). This is because in the past unboxed pin headers were used and the position of the "nose" did not matter. In such a case please contact Doepfer or one of their dealers and order a suitable bus cable.

Notes: - High-grade patch cable designed for modular units
- 3.5mm mono jack plugs
- Length: 120cm
- Blue finish

Notes: - High-grade patch cable designed for modular units
- 3.5mm mono jack plugs
- Length: 15cm
- Yellow finish

Notes: - High-grade patch cable designed for modular units
- 3.5mm mono jack plugs
- Length: 200cm
- Green finish

Notes: - High-grade patch cable designed for modular units
- 3.5mm mono jack plugs
- Length: 30cm
- Black finish

Notes: - High-grade patch cable designed for modular units
- 3.5mm mono jack plugs
- Length: 50cm
- Grey finish

Notes: - High-grade patch cable designed for modular units
- 3.5mm mono jack plugs
- Length: 50cm
- Angled connector on one end
- Orange finish

Notes: - High-grade patch cable designed for modular units
- 3.5mm mono jack plugs
- Length: 50cm
- Transparent cabling

Notes: - High-grade patch cable designed for modular units
- 3.5mm mono jack plugs
- Length: 80cm
- Red finish

Notes: Patch cable for modular synthesizer 80 cm, transparent, mono jack plug 3.5 mm at each end.

Notes: The A-100LC1v is a smaller version of the A-100LC3 with 48 HP of space. It is made out of raw wood, a black coating gives the Eurorack frame a vintage look. The built-in power supply, type A-100SSB, delivers up to 380 mA at +12 V and -12 V as well as 100 mA at +5 V.

The A-100LC1v comes equipped with one 48 HP measuring row for 3U modules. Its power supply features eight connectors for oscillators, filters and so forth. The case is connected to the grid via an IEC power socket.

Notes: Module A-103 is a voltage controlled low pass filter with 18dB/octave slope. The circuit is based on a modified transistor ladder (Moog ladder) and is a reproduction of the legendary TB303 filter.

As for the rest the A-103 is identical to the A-120 Moog low pass filter (same controls, inputs/outputs) only the filter sound is different.

Notes: A-105-4 is our first polyphonic filter and contains four
identical 24dB Lowpass filters (SSM2044 type). It has
available common manual controls and CV inputs with
attenuators for these parameters:

Frequency (F)

Frequency Modulation Intensity (FM)

Resonance (Q)

Audio Input Level (L)
Each filter has available a separate FM input as well as an Audio Input and Output. The FM input is typically connected to the output of the associated envelope generator (e.g. A-141-4).
The envelope amount for all four filters is controlled by the FM knob and the CVFM input by means of four built-in VCAs, which are controlled by the FM control and CVFM input. This allows also voltage control of the envelope amounts.

In addition common frequency modulation for all filters is possible (e.g. by an LFO). For this the CVF input with attenuator can be used. The range of the audio input level control (L) allows also clipping/distortion with typical A-100 audio levels
(e.g. from A-111-4) at the filter inputs. Even this parameter is voltage controllable as well as the resonance (Q).
Application: polyphonic patches (four VCFs with same parameters).

Notes: VCO:

- Tune: manual tune control (with an internal jumper the range can be set to ~ +/-1 half an octave or ~ +/-2.5 octaves)
- Oct: range switch -1 / 0 / +1 octave
- Mod: modulation depth (attenuator wired to the Mod. socket)
- Dest: switch that is used to address the modulation to frequency modulation (position FM) or pulsewidth modulation (positon PM), in centre positon no modulation
- PW: manual pulsewidth control for rectangle waveform, PW can be also modulated by the Mod. input as mentioned above
- Wave: waveform switch (sawtooth / off / triangle), the sum of the waveform chosen by this switch and the rectangle is fed into the VCF (to turn the rectangle off the PW control has to be set fully CCW or fully CW)
- 1V/Oct. (socket): external CV input for VCO frequency (1V/octave)
- Access to internal bus CV (via jumper, optional, please remove the bus jumper if this feature is not used to avoid unwanted frequency modulation as then the unused CV line of the bus works as a kind of antenna)
- Triangle core VCO, frequency range about 32Hz ... 8kHz

Balance unit:

- The balance unit is made of two VCAs which are controlled by the sum of manual Balance control and the balance CV input in the opposite direction.
- The audio input of VCA1 is hard-wired to the VCO output, audio input 2 is connected to the socket Ext.In.
- The output of the balance unit is used as audio input for the VCF
- Bal.: manual balance control, fully CCW the internal VCO is used, fully CW the external signal (Ext.In) is used, at centre position both signals have about the same level
- CV Bal.: CV input for balance (range about 0...+5V)
- Ext. In: external audio input for VCA2, about 5 Vpp level required for similar loudness as the internal VCO
- This socket is normalled to the internal VCO suboctave f/2 signal (rectangle with half the frequency), if no external signal is applied the suboctave signal is used as the second signal for the balance unit

VCF:

- 24 dB low pass
- Frq: manual frequency control
- FM1: frequency modulation depth (attenuator wired to the VCF FM1 socket, the socket is normalled to the internal Envelope signal and then FM1 controls the modulation depth of the internal envelope applied to the filter)
- FM2 (socket) : second CV input for VCF without attenuator (about 1V/octave), can be used e.g. for VCF tracking by connecting the same CV which is used also for the VCO frequency
- Res: manual resonance control (up to self oscillation)
- If the VCO is turned off (waveform switch = centre position, pulsewidth control = fully CCW or CW) and the VCF resonance is set to maximum the module can be used as a sine oscillator, the tracking at socket VCF FM2 is about 1V/octave (not as precise as the VCO but much better than most other filters)
- ~ 11 octaves frequency range (~ 10 Hz ... 20kHz)

VCA:

- Gain: manual amplitude control (initial gain), can be used to open the VCA without envelope signal
- VCA (switch): used to switch between gate and envelope as control signal for the VCA, in centre position the VCA is not controlled by envelope or gate
- Note: when gate is used the VCA is controlled directly by the gate signal (i.e. hard on/off), this may lead to clicking noise under certain conditions (especially with low VCO/VCF frequencies)
- Special control scale: exponential scale in the range from about -20dB to -80/90dB, linear scale from about -20dB to 0dB
- Remark: this special control scale results in a loudness behaviour that is a bit different from pure linear or exponential VCAs
- Out: audio output of the module (= VCA output)

Envelope:

- Gate (socket): Gate input (min. +5V), can be normalled to the bus gate signal by means of a jumper
- Att: manual control for Attack
- D/R: manual control for Decay/Release
- Env. (switch): used to switch between A/D, ADSR and A/R mode of the envelope generator, in centre position (ADSR) the sustain level is fixed to about 50%
- Envelope (socket): envelope output (about +10V)
- CVT (socket): CV input for time control, by means of two internal jumpers one can select which time parameters are controlled by the CVT input (e.g. A only or D/R only or A/D/R) and in which direction (i.e. if an increasing CVT shortens or stretches the time parameter in question)
- Envelope LED display
- Attack time range: ~ 1ms ... 5 sec (can be extended by using the CVT input)
- Decay/Release time range: ~ 1ms ... 15 sec (can be extended by using the CVT input)

Notes: VCO:

- Tune: manual tune control (with an internal jumper the range can be set to ~ +/-1 half an octave or ~ +/-2.5 octaves)
- Oct: range switch -1 / 0 / +1 octave
- Mod: modulation depth (attenuator wired to the Mod. socket)
- Dest: switch that is used to address the modulation to frequency modulation (position FM) or pulsewidth modulation (positon PM), in centre positon no modulation
- PW: manual pulsewidth control for rectangle waveform, PW can be also modulated by the Mod. input as mentioned above
- Wave: waveform switch (sawtooth / off / triangle), the sum of the waveform chosen by this switch and the rectangle is fed into the VCF (to turn the rectangle off the PW control has to be set fully CCW or fully CW)
- 1V/Oct. (socket): external CV input for VCO frequency (1V/octave)
- Access to internal bus CV (via jumper, optional, please remove the bus jumper if this feature is not used to avoid unwanted frequency modulation as then the unused CV line of the bus works as a kind of antenna)
- Triangle core VCO, frequency range about 32Hz ... 8kHz

Balance unit:

- The balance unit is made of two VCAs which are controlled by the sum of manual Balance control and the balance CV input in the opposite direction.
- The audio input of VCA1 is hard-wired to the VCO output, audio input 2 is connected to the socket Ext.In.
- The output of the balance unit is used as audio input for the VCF
- Bal.: manual balance control, fully CCW the internal VCO is used, fully CW the external signal (Ext.In) is used, at centre position both signals have about the same level
- CV Bal.: CV input for balance (range about 0...+5V)
- Ext. In: external audio input for VCA2, about 5 Vpp level required for similar loudness as the internal VCO
- This socket is normalled to the internal VCO suboctave f/2 signal (rectangle with half the frequency), if no external signal is applied the suboctave signal is used as the second signal for the balance unit

VCF:

- 24 dB low pass
- Frq: manual frequency control
- FM1: frequency modulation depth (attenuator wired to the VCF FM1 socket, the socket is normalled to the internal Envelope signal and then FM1 controls the modulation depth of the internal envelope applied to the filter)
- FM2 (socket) : second CV input for VCF without attenuator (about 1V/octave), can be used e.g. for VCF tracking by connecting the same CV which is used also for the VCO frequency
- Res: manual resonance control (up to self oscillation)
- If the VCO is turned off (waveform switch = centre position, pulsewidth control = fully CCW or CW) and the VCF resonance is set to maximum the module can be used as a sine oscillator, the tracking at socket VCF FM2 is about 1V/octave (not as precise as the VCO but much better than most other filters)
- ~ 11 octaves frequency range (~ 10 Hz ... 20kHz)

VCA:

- Gain: manual amplitude control (initial gain), can be used to open the VCA without envelope signal
- VCA (switch): used to switch between gate and envelope as control signal for the VCA, in centre position the VCA is not controlled by envelope or gate
- Note: when gate is used the VCA is controlled directly by the gate signal (i.e. hard on/off), this may lead to clicking noise under certain conditions (especially with low VCO/VCF frequencies)
- Special control scale: exponential scale in the range from about -20dB to -80/90dB, linear scale from about -20dB to 0dB
- Remark: this special control scale results in a loudness behaviour that is a bit different from pure linear or exponential VCAs
- Out: audio output of the module (= VCA output)

Envelope:

- Gate (socket): Gate input (min. +5V), can be normalled to the bus gate signal by means of a jumper
- Att: manual control for Attack
- D/R: manual control for Decay/Release
- Env. (switch): used to switch between A/D, ADSR and A/R mode of the envelope generator, in centre position (ADSR) the sustain level is fixed to about 50%
- Envelope (socket): envelope output (about +10V)
- CVT (socket): CV input for time control, by means of two internal jumpers one can select which time parameters are controlled by the CVT input (e.g. A only or D/R only or A/D/R) and in which direction (i.e. if an increasing CVT shortens or stretches the time parameter in question)
- Envelope LED display
- Attack time range: ~ 1ms ... 5 sec (can be extended by using the CVT input)
- Decay/Release time range: ~ 1ms ... 15 sec (can be extended by using the CVT input)

Notes: Module A-112 is the combination of a voltage controlled 8 Bit Sampler and a wavetable oscillator. On top of it the module is able to generate some special effects. A-112 was designed as an additional sound source with the typical sounds of the early 8 bit samplers and is not comparable with the modern polyphonic MIDI samplers available on the market.

Sampling mode: 8 bit audio resolution, 128kB memory in 2 banks 64kB each (equivalent to 2 seconds of sampling time for each bank with 32 kHz sampling rate), audio input with attenuator, overload display in record mode (gate LED), possibility of MIDI Dump to store sounds in a computer via MIDI, non-volatile memory for the 2 samples in the module, manual tune control for adjustment of sampling rate for record and play, CV input (~ 1V/Oct), both manual tune and CV determine the sampling rate respectively the pitch (pitch range is 5 octaves), gate input (not a trigger: the sample starts at the positive edge of the gate signal and is played as long as gate is high or until the end of the sample is reached), manual Gate button, non-filtered audio output (thus quantizing noise can be used as an element of the sound intentionally).

Wavetable mode: special appearance of the sampling mode when playing a sample, the audio input is now used as a second control voltage input for moving through the sample in 256 byte wide loops (wavetables). The control voltage required to move through all wavetables applied to the input "Wave CV In" is in the range -2.5V (wavetable 1) ... 0V (wavetable 127) ... +2.5V (wavetable 256) when control "Atten." is set fully clockwise. To achieve the typical wavetable oscillator sounds the sampling memory must contain corresponding wavetable data (e.g. loaded via MIDI dump). These data contain a set of wavetables with different harmonic content (e.g. a filter sweep) to get the typical wavetable sound while moving through the tables via CV. But you may also use a "normal" sample and go through the sample with CV to obtain partially amazing sounds never heard before. You may use for example sampled speech and go with CV through the syllables or speech shreds to get really very extreme sounds. An ideal addition for this feature is the Offset/Attenuator module A-183-2 which can be used to adjust the position of the wavetable (Offset) and the modulation depth (Att.). The corresponding jumper of the A-183-2 has to be set to bipolar offset (as the A-112 requires -2.5V...+2.5V to pass through all 256 wavetables). As modulation source an LFO (A-145, A-146, A-147, A-143-3), ADSR (A-140, A-141, A-142, A-143-1/2) or a random voltage (A-118, A-149-1) may be used. Even a ribbon controller (A-198 or R2M), the Theremin module A-178, the Joystick A-174 or the Wheels module A-174-2 are useful to drive through the wavetables.

Effects: Additionally, the module offers - in a way free of charge - some effects like delay, reverse delay, pitch shifting or freeze. But it has to be pointed out that due to the 8 bit audio resolution these effects are not comparable to high quality effect units and should be understand as an extra for nothing. The A-112 is not an effects unit!

The sampling time of the A-112 is about 1...30 seconds corresponding to a sampling frequency range of about 60kHz...2kHz (64kB@60kHz ~ 1 s, 64kB@2kHz ~ 30 s).

Technical note: the module uses a battery for the non-volatile storage of the sampling data. Batteries have a limited lifespan and have to be inspected at least every two years. For details please refer to the FAQ page of our website: Lifespan of rechargeable batteries (used for memory backup).

Notes: Module A-115 is a four-way frequency divider. The frequency of a signal at the input is halved (half frequency = first sub-octave), quartered (1/4 frequency = second sub-octave), and so on. In this way, the DIVIDER produces four sub-octaves (F/2 down to F/16).

At the output, the A-115 produces a summed mix of the original and the four sub-octaves. There are attenuators to control the amount (i.e. Amplitude) of the original signal and each of the sub-octaves.

Bear in mind that the sub-octaves output by the A-115 are all true square waves. At the output there are always four square waves and the original signal available.

Notes: Module A-118-2 is the slim version of module A-118-1 and offers essentially the same features as the A-118-1. But the distances between the controls are smaller and rubberized small-sized knobs are used. In return the front panel has 4 HP only which is half the width of the A-118-1. The module is primarily planned for applications where only limited space is available. The functional difference between A-118-1 and A-118-2 is the additional T&H/S&H unit which is not included in the A-118-1.

The module generates the signals white noise, colored noise, continuous random voltage and stepped random voltage (derived from the continuous random voltage by means of a S&H/T&H unit).

The noise signal is generated 100% analog by amplification of the noise of a transistor. White and colored noise are usually used as audio sources. The random voltages are normally used as control voltages (e.g. for filter frequency or any other voltage controlled parameter).
The A-118-2 gives you the ability to mix the relative amounts of Red (low frequency component) and Blue noise (high frequency component) in the colored noise output.

For the continuous random voltage the rate of change (Rate) and amplitude (Level) of the random voltage can be adjusted. The continuous random voltage is derived from the colored noise signal by low pass filtering. Consequently the settings of the controls for the colored noise (Blue, Red) affect the behavior of the random voltage! A dual color LED (red = positive / yellow = negative output voltage) indicates the continuous random voltage.

The continuous random voltage is used as source for the S&H/T&H unit. The type of operation can be set to S&H (sample and hold) or T&H (track and hold). When T&H is chosen the output signal follows the input signal (= continuous random voltage) as long as the Clock input is "high". As soon as the clock signal changes to "low" the last voltage is stored. When S&H is chosen the input signal (= continuous random voltage) is sampled at the rising edge of the Clock signal.

For the Clock signal a "digital" signal (e.g. Clock, Gate, rectangle output of an LFO) is required. It does not work with slowly changing continuous CV signals. Another dual color LED (red = positive / yellow = negative output voltage) indicates the stepped random voltage.

Controls:

Blue: share of the high frequencies in the the colored noise output
Red: share of the low frequencies in the the colored noise output
Rate: rate of change of the continuous random voltage
Level: amplitude of the continuous random voltage
TH/SH: switches between T&H and S&H

Inputs and outputs:

RND: continuous random voltage output (with LED display)
TH/SH: stepped random voltage output (with LED display)
Clk: Clock input of the S&H/T&H unit
C Noise: colored noise output
W Noise: white noise output

Important notes:

After power on it takes a few minutes until the two noise signals and the random signals are generated. The module is not faulty when after power on the signals do not appear immediately!

The S&H/T&H function is realized by pure analog circuitry (electronic switch followed by a holding capacitor and buffer). Consequently the output voltage drifts a bit in the holding state because the capacitor is discharged by parasitic resistors. The drift depends also upon environmental conditions like humidity or temperature.

Dimensions
4 HP
40 mm deep

Current Draw
20 mA +12V
20 mA -12V

Notes: Module A-119 (External Input / Envelope Follower) is designed to allow external audio signals to be integrated into the System A-100. It comprises a pre-amp, envelope follower, and comparator.

The pre-amp has two inputs: an unbalanced input for line level signals, with a gain factor of from 0 to 20, and a balanced input with a gain factor of from 0 to 500, for insertion of low level signals, for instance from a microphone or electric guitar.

The Envelope Follower reads the signal level of the input, and puts out a proportional voltage as an envelope at its own output.

The comparator generates a gate signal whenever the input goes above an adjustable trigger threshold.

Three LED's help you keep track of overload, the envelope, and the gate signal.

Notes: Module A-124 is a special 12dB multimode filter using the "strange" filter circuit of the "EDP Wasp" (an analog synthesizer with black/yellow case built end of the seventies, manufactured by the UK company "Electronic Dream Plant" with Chris Huggett und Adrian Wagner). This design "abuses" digital inverters as analog operational amplifiers leading to distortions and other "dirty" effects that generate the specific sound of this filter. The filter is equipped with a band pass output and a combined low/notch/high pass output. For this output a control knob defines the relation between low and high pass signal. If both signals appear at the same level (i.e. middle position of the Mix knob) one obtains a notch filter. Otherwise the low or high pass signal predominates. The module does not feature self-oscillation in contrast to most of the other filters of the A-100 system.

Inputs: Audio In, CV In (2x)
Outputs: Bandpass Out, Low/Highpass Mix-Out
Controls: Audio and CV attenuator, Frequency, Resonance, LP/HP Mix

The function and operation of this module is very similar to the module SEM VCF A-106-5. But the sound of both filters is very different! The only functional difference is the position of the sockets and controls, and the function of the controls CV2 (A-124: normal attenuator, A-106-5: polarizer).

- 3U Eurorack module, 8HP wide, 45mm deep
- Current draw 30mA

Notes: Module A-130-2 is the slim version of module A-132-3 and offers essentially the same features. But the distances between the controls are smaller and rubberized small-sized knobs are used. In return the front panel has 4 HP only which is half the width of the A-132-3. The module is primarily planned for applications where only limited space is available.

The module is composed of two identical voltage controlled amplifiers (VCA). Each VCA has a manual gain control (also named Initial Gain) and a control voltage input with attenuator. The character of the control scale can be switched to linear or exponential. All inputs and outputs are DC coupled. Consequently the VCAs can be used to process both audio and control voltages (e.g. for voltage control of the level of LFO or envelope signals). The signal input has no attenuator available but is capable to process up to 16Vpp signals (i.e. -8V...+8V) without distortion. For the processing of higher levels an external attenuator (e.g. A-183-1) is recommended.

The amplification range is 0...1. Even with a higher external control voltage the amplification remains at 1 (kind of "amplification clipping" at 1).

Controls (for each of both units):

- Gain: manual gain control (Initial Gain) in the range 0...1
- CV: attenuator for the CV input
- Lin/Exp: switches the VCA characteristic to linear or exponential, in center position the VCA is off (mute function)

Inputs and outputs (for each of both units):

- CV: control voltage input, min. +5V required for max. amplification (1) with CV control fully CW and Gain fully CCW
- In: signal input, max. 16Vpp (+8V...-8V) without distortion
- Out: signal output

Notes: A-133-2 is the slim version of the A-133 but has some additional features and improvements available compared to the A-133.

Module A-133-2 can be used for a lot of applications: as a simple VCA, or a voltage controlled polarizer/attuverter, or a voltage controlled inverter up to a DC coupled ring modulator. In principle the module contains two special voltage controlled amplifiers (VCAs) that allow both positive and negative amplification.

The overall amplification is definded by the sum of the voltage generated by the Man control, the external control voltage CV and the position of the CV control which works as an attenuator for the external control voltage. Without external CV the amplification is +1 when the Man control is fully CW. In the center position the amplification is zero and fully CCW it's -1 (i.e. the incoming signal is inverted). By means of the external control voltage CV the manually adjusted amplification can be modulated. CV can be both positive or negative (i.e. bipolar) to obtain positive or negative amplification values controlled by the external CV.

In addition the CV signal can be modulated via the modulation control input Mod by means of another control voltage. The Mod socket is normalled to +5V, i.e. a constant positive voltage is used as modulation CV provided that no plug is inserted into the Mod socket.

The current amplification is displayed by a dual color LED (note: it's not a signal display but indicates the amplification, probably yellow = positive amplification, red = negative amplification)
Application examples:
voltage controlled amplifier (VCA) with pure positive overall amplification (Man + CV)
voltage controlled inverter with pure negative overall amplification (Man + CV)
voltage controlled polarizer/attuverter overall amplification changing between positive and negative (Man + CV)
DC coupled ring modulator with offset feature, the "classical" ring modulator corresponds to Man=0 and symmetrical audio signals for In and CV
additional effects by means of the modulation feature of the CV signal (using the Mod input)

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: A-135-2 is a miniature version of the A-135-1. Behind a front panel with 8 HP only four linear VCAs (voltage controlled amplifiers) and a voltage controlled mixer based on the VCAs are available.

Controls, In/Outputs and Functions of each VCA:

- Level (manual control of the VCA amplification), small rubberized knob (L1...L4)
- Control voltage input with associated attenuator (CV1...CV4), for the full VCA control range about 0...+5V control voltage are required (attenuator fully clockwise), for higher control voltages the attenuator is used, the attenuators are without knobs, just plastic shafts with white marker
- Signal Input
- Signal Output
- All inputs and outputs are DC coupled. Consequently the VCAs can be used to process both audio and control voltages (e.g. to control the level of LFOs or envelopes)
- The signal input is not equipped with an attenuator. But the VCAs can process all signals up to 15Vpp / -7.5...+7.5V without clipping. In case of higher levels an external attenuator is required (e.g. A-183-1).
- The available amplification range is 0...1, the maximal amplification is 1 (i.e. it "clips" and remains at 1 even if the control voltage goes beyond the value that corresponds to amplification 1)

Functions of the voltage controlled mixers:

- Two outputs ("Selected" and "All")
- Selected output: the ouput if a VCA is removed from this sum signal when a plug is inserted into the corresponding VCA output.
- All output: sum of all VCA outputs, regardless of inserted plugs into the VCA outputs
- The maximal amplification is about 0.6 to avoid clipping at the mixer outputs (otherwise the outputs may distort with 15Vpp signals at each signal input and full amplifications)

Special functions of the voltage controlled mixers (selectable by internal jumpers):

- Dual Stereo VCA: In this case the control unit of VCA1 (L1 + CV1) affects also VCA3 and the control unit of VCA2 (L2 + CV2) affects also VCA4, the control units of VCA2 and VCA4 are out of operation
- Quad VCA: In this case the control unit of VCA1 (L1 + CV1) affects all four VCAs. The control units of VCA2, VCA3 and VCA4 are out of operation. In this mode the module has the same function as module A-132-2. That's why module A-132-2 will be discontinued.
- Normalling of the signal inputs: by means of internal jumpers signal input 1 can be normalled to signal input 2, signal input 2 to signal input 3 and signal input 3 to signal input In 4. That way the same input signal can be distributed to four different channels by means of control voltages (e.g. quadrophonic distribution of audio signals). Suitable control voltage sources are e.g. A-144 (Morphing Controller) or A-143-9 (Quadrature LFO).

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: Module A-138n is a simple four channel mixer, which can be used with either control voltages or audio signals. Each of the four inputs has an attenuator available. The output is twice available (two sockets, hard-wired like a multiple).

The module is the slim version of module A-138a and offers nearly the same features. But the distances between the controls are smaller and rubberized small-sized knobs are used. In return the front panel has 4 HP only which is half the width of the A-138a. The module is primarily planned for applications where only limited space is available. The only functional difference compared to the A-138a is the missing attenuator for the (dual) output.

Notes: Compact and simple four-input mixer module from Uncle Dieter. Linear pots make it suited to mixing CV signals but it can also handle audio. Mixed signal hard-wired to two sockets.

Supplier notes:
Module A-138n is a simple four channel mixer, which can be used with either control voltages or audio signals. Each of the four inputs has an attenuator available. The output is twice available (two sockets, hard-wired like a multiple).

HP : 4

Notes: A-138s is a simple but useful 4-in-2 mixing tool. It has four inputs available. Each input is equipped with an attenuator (Level) and a panning control that is used to distribute the signal to the left and right output. Beyond stereo mixing it is equally suited to create variable parallel routings. For example: Any of the four inputs may be routed in variable intensity to feed two filters.

You may regard the A-138s as a smaller version of the A-138m Matrix Mixer.

Inputs and outputs are DC coupled, i.e. the module can be used for the mixing of control signals too.

- 3U Eurorack module, 8 HP wide, 30 mm in depth
- Power consumption: 10 mA at +12 V and 10 mA at -12 V

Notes: A-138s is a simple but useful 4-in-2 mixing tool. It has four inputs available. Each input is equipped with an attenuator (Level) and a panning control that is used to distribute the signal to the left and right output. Beyond stereo mixing it is equally suited to create variable parallel routings. For example: Any of the four inputs may be routed in variable intensity to feed two filters.

You may regard the A-138s as a smaller version of the A-138m Matrix Mixer.

Inputs and outputs are DC coupled, i.e. the module can be used for the mixing of control signals too.

- 3U Eurorack module, 8 HP wide, 30 mm in depth
- Power consumption: 10 mA at +12 V and 10 mA at -12 V

Notes: Module A-140-2 contains two ADSR type envelope generators behind a front panel with 8 HP only.

Each ADSR provides these controls and in/outputs:

- LED (displays the envelope output)
- A: manual Attack control
- D: manual Decay control
- S: manual Sustain control
- R: manual Release control
- Gate Input
- Retrigger Input
- CVT Input with attenuator (CVT = CV Time)
- Envelope Output 1
- Envelope Output 2

The output voltage range for each envelope is 0 - 10V. The time range of Attack/Decay/Release is about 1ms to 30s.

By means of internal jumpers one can select which time parameters are controlled by the CVT input (e.g. D only or D+R or A+D+R) and in which direction (i.e. if an increasing CVT shortens or stretches the time parameter in question).

Socket CVT can be normalled to an internal fixed voltage (i.e. the switching contact is connected to an internal fixed voltage). That way it's possible to change all time parameters simultaneously by means of the CVT control.

Another jumper is used to set output 2 to normal or inverted envelope.

And another jumper is used for the normalling of Gate 2 to Gate 1 (i.e. ADSR#2 is also triggered by Gate 1).

Two more jumpers are used for the optional bus access to the gate signal of the bus for each ADSR. Changing the positions of the mentioned jumpers allows to modify the factory settings.

Notes: The module contains two ADSR type voltage controlled envelope generators with exponential curve shapes (charge/discharge curves of a capacitor) behind a front panel with 8 HP only.

Each ADSR provides these controls and in/outputs:

- LED (displays the envelope output)
- A: manual Attack control
- D: manual Decay control
- S: manual Sustain control
- R: manual Release control
- Gate Input
- Retrigger Input
- CVT Input with attenuator (CVT = CV Time)
- Envelope Output 1
- Envelope Output 2

The output voltage range for each envelope is 0 - 10V (10V = attack peak).

The time range of Attack/Decay/Release is about 1ms to 30s.

By means of internal jumpers one can select which time parameters are controlled by the CVT input (e.g. D only or D+R or A+D+R) and in which direction (i.e. if an increasing CVT shortens or stretches the time parameter in question).

Socket CVT can be normalled to an internal fixed voltage (i.e. the switching contact is connected to an internal fixed voltage). That way it's possible to change all time parameters simultaneously by means of the CVT control.

Another jumper is used to set output 2 to normal or inverted envelope.

And another jumper is used for the normalling of Gate 2 to Gate 1 (i.e. ADSR#2 is also triggered by Gate 1).

Two more jumpers are used for the optional bus access to the gate signal of the bus for each ADSR.

Notes: Module A-143-9 is a derivative of our planned thru-zero quadrature VCO. It is a voltage controlled sine LFO with 4 outputs. The phase shift between the outputs is 90 degrees. The sine shifted by 90 degrees is also called cosine, the sine shifted by 180 degrees is nothing but the inverted sine, and the sine by 90 degrees is nothing but the inverted cosine.

The frequency range is from some minutes to frequencies beyond audio with three ranges selected by a toggle switch:

- Switch position H: about 30 Hz ... 3.5 kHz with the manual frequency control ("Frq."), beyond 20 kHz with additional external CV
- Switch position M: about 1 Hz ... 150 Hz with the manual frequency control ("Frq.")
- Switch position L: about 0,1 Hz ... 10 Hz with the manual frequency control ("Frq."), down to several minutes with additional external CV

Two exponential frequency control inputs are available: CV1 without attenuator and CV2 with polarizer. Consequently the module can be used even as an experimental sine VCO but does not feature an exact 1V/oct CV input! The precision CV input will be left to the thru-zero quadrature VCO.

Two LEDs display the positive and negative share of the sine output.

The core of the module is a so-called quadrature circuit that generates a sine a cosine signal with very low distortion. The quality of the sine/cosine signals are much better than those generated by a waveform converter with a sawtooth or triangle signal as starting point.

The output levels are about 5 Vss (+/-2.5V) but can be adjusted internally by a trimming potentiometer (P5 "Shape").

Typical applications:

- External sine/cosine oscillator for the frequency shifter A-126
- Modulations with pure sine/cosine waveforms
- Quadrature/barberpole effects (e.g. with the voltage controlled mixer A-135)
- Experimental sine/cosine VCO (e.g. for FM sounds)

Many users suggested to add a common output level control, i.e. four VCAs with one common control (manual + CV without attenuator + CV with polarizer) for the output levels. This is why we also designed the Quad VCA module A-132-2 with the possibility of an internal default connection to the four outputs of the A-143-9 (no soldering required, short 10 pin flat cable with removable connectors on both ends).

The A-143-9 is also a meaningful addition for the Frequency Shifter module A-126. It enables frequency shifting even below 50 Hz generating e.g. these mellow beat sounds with a few Hz frequency shifting only. The following document describes how to connect the A-126 and the A-143-9: A126_A143_connection.pdf.

The thru zero version of the A-143-9 with temperature compensation is the module A-110-4.

Notes: Module A-145-4 is a simple quad LFO (Low Frequency Oscillator). Not a very "exciting" module, just a bread-and-butter device and a simple demon for work. Virtually in every modular system several LFOs are required for modulation purposes. The module contains four simple LFOs with the waveforms triangle and rectangle. A dual colour LED (red = positive / yellow = negative output voltage) indicates the triangle output of each LFO. The frequency range can be chosen for each LFO individually by means of a jumper between about 50 Hz ... 0.04 Hz (about 20 seconds, jumper removed) and about 2Hz ... 0.002 (about 8 minutes, jumper installed).

The module can be treated as a slimmed version of the quad LFO A-143-3 as it has similar features available. But the distances between the controls are smaller and rubberized small-sized knobs are used. In return the front panel has 4 HP only which is less than one third of the A-143-3. The module is primarily planned for applications where only limited space is available. The functional difference compared to the A-143-3 are the missing sawtooth outputs and frequency range switches.

Notes: Module A-145-4 is a simple quad LFO (Low Frequency Oscillator). Not a very "exciting" module, just a bread-and-butter device and a simple demon for work. Virtually in every modular system several LFOs are required for modulation purposes. The module contains four simple LFOs with the waveforms triangle and rectangle. A dual colour LED (red = positive / yellow = negative output voltage) indicates the triangle output of each LFO. The frequency range can be chosen for each LFO individually by means of a jumper between about 50 Hz ... 0.04 Hz (about 20 seconds, jumper removed) and about 2Hz ... 0.002 (about 8 minutes, jumper installed).

The module can be treated as a slimmed version of the quad LFO A-143-3 as it has similar features available. But the distances between the controls are smaller and rubberized small-sized knobs are used. In return the front panel has 4 HP only which is less than one third of the A-143-3. The module is primarily planned for applications where only limited space is available. The functional difference compared to the A-143-3 are the missing sawtooth outputs and frequency range switches.

Notes: Module A-147-2 is the successor of the VCLFO A-147 but offers much more features than the predecessor. The module is made of these sub-units:

- VCLFO: voltage controlled low frequency oscillator
- VCA: voltage controlled amplifier, switchable to voltage controlled polarizer
- VC delay unit: voltage controlled linear attack envelope (only one parameter: attack) for delayed LFO operation in combination with the VCA (e.g. delayed vibrato/tremolo)

LFO: The voltage controlled LFO has the waveforms Triangle, Sine, Sawtooth and Rectangle available and features a Reset/Sync input. Triangle/Sine and Rectangle are displayed by means of dual-colour LEDs (probably red/green), Sawtooth has a unicolor LED available (probably blue). The output levels are about -4V...+4V for Triangle, Sine and Rectangle. The Sawtooth level is about 0...+8V.

The CV control can be switched to attenuator or polarizer ("CV Mode" switch). In polarizer mode the CV inputs affects the frequency in the reverse manner when the CV control is left from the centre position. In the centre position CV has no effect and right from the centre the control works like a normal attenuator. The frequency range (without external CV) is from about 0,005 Hz (i.e. about 3 minutes per period) to 200 Hz (with external CV max. frequency about 1kHz). In addition a ultra-low mode can be activated by means of an internal jumper. When the ultra-low jumper is set a fixed voltage is connected to the switching contact of the "LFO CV" socket. In polarizer mode of the CV control that way extremely low frequencies (up to one hour period and more) are possible. For this a jumper has to be installed on the pin header JP6. In the factory a dummy jumper is installed on the pin header JP7 "Dummy". JP7 has no function and is used only for "parking" of the jumper. Simply remove the jumper from JP7 and plug it on JP6. JP6 is located behind the CV control.

VCA: This is a linear VCA that can be switched to "normal" VCA (i.e. kind of a voltage controlled attenuator) or voltage controlled polarizer ("VCA Mode" switch). In the "normal" VCA mode amplification +1 is achieved with about +5V control voltage. In polarizer mode the amplification ranges from about -0.5 (i.e. inverted signal with about 50% level) with 0V CV to +0.5 (i.e. non-inverted signal with about 50% level) with +5V CV. With about +2.5V CV the signal is suppressed. Details about the functioning of a voltage controlled polarizer can be found in the description of the module A-133. In this mode the VCA can be treated also a DC coupled ring modulator (similar to A-114).

The VCA of the A-147-2 has three sockets available: "In" (signal input), "Out" (signal output) and "CV" (control voltage input).

The Triangle Output of the LFO is normalled to the VCA signal input by means of the switching contact of the "VCA In" socket. If another LFO waveform (or any other signal) should be processed by the VCA the corresponding signal has to be patched to the "VCA In" socket. The VCA can be used also independently from the LFO and the Delay CV. In this case the VCA sockets In, Out and CV have to be patched accordingly. The VCA can be used also as waveshaper for the LFO signals (e.g. by patching VCA In and VCA CV to different LFO signals, if necessary via attenuator A-183-1 or offset generator/attenuator A-183-2).

Attack/Delay: The third sub-unit of the module is a simple, voltage controlled envelope generator that has only the parameter "Delay" (or Attack) available. This unit generates a linear increasing voltage that starts from 0V after each Delay Reset until it reaches about +5V. Then the voltage remains at +5V until the next Delay Reset occurs. The inclination or gradient is controlled by the manual Delay control and the Delay control voltage ("Delay CV" input). The waveform is linear, the control scale is exponential. The output voltage is displayed by a green LED and available at the "Delay Out" socket.

The manual Delay control ranges - without external "Delay CV" - from about 5ms (fully CW) up to 2 minutes (fully CCW). By means of an external voltage applied to the "Delay CV" socket this range can be extended. A rising CV shortens the delay time (behaviour like a VCO)!

The Delay output voltage ranges from about 0V to +5V. The rising edge of the gate, clock or trigger signal applied to the "Delay Reset" sockets resets the Delay output voltage to 0 V.

"Delay Out" is normalled to the VCA CV input by means of the switching contact of the "VCA CV" socket and consequently controls the Triangle level provided that no other patch is made. A typical example is the usage of a Gate signal (e.g. from a USB/Midi-to-CV/Gate interface) as Delay Reset. That way a delayed vibrato or tremolo can be realized if the VCA output is patched to the frequency CV input of a VCO (or VCF), or the CV input of a VCA.

Notes: Module A-148 (Dual S&H) has two identical sample & hold modules, designed to produce 'staircase' voltages. The signal present at the sample input is sampled at a rate set by the signal at the trigger input, and held at that voltage at the S&H output.

The exact shape of the staircase depends on the sort of waveform at the sample input: NOISE or RANDOM signals produce random patterns; an LFO produces rising or falling staircase patterns.

Two LEDs for each S&H indicate the voltage (positive or negative) of the sampled signal.

Notes: Module A-150-1 (Dual VCS) contains two separate voltage-controlled switches.

Each switch has a control voltage input, a common Out / Input, and two In / Outputs. The switches are bi-directional: they can work in both directions, so can connect one input to either of two outputs, or either of two inputs to one output. Voltages in the range -8V...+8V at the O/I resp. I/O sockets can be processed by the module.

Two LEDs show which in / output is active (i.e. which is connected to the common out / input).