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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: 30cm
- Black finish

Notes: - High-grade patch cable designed for modular units
- 3.5mm mono jack plugs
- Length: 50cm
- Grey 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-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: 80cm
- Red 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: 120cm
- Blue 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: Patch cable for modular synthesizer 80 cm, transparent, mono jack plug 3.5 mm at each end.

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

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

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

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

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

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

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, 8HP, constructed from anodised aluminium, silver.

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

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

Notes: - 6.3 mm jack male mono to 3.5 mm jack male mono
- Length: 1.5 metres

Notes: - 6.3 mm jack male mono to 3.5 mm jack male mono
- Length: 3 metres

Notes: Blank panel, 42HP, 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: 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.

Notes: Module A-180-3 is a dual buffered 1-in-3 multiple. The signal applied to the input socket appears as a buffered signal at the three output sockets. Each output has its own buffer, i.e. the three output sockets are not simply connected to each other. The lower output of the upper unit is normalled in the factory to the input of the lower unit. That way the module works as a single 1-in-6 buffered multiple provided that no signal is applied to the input of the lower unit. But it's also possible to pick-up the bus CV and normalize the input socket of the lower unit to the bus CV.

Application: copying/buffering of CV, gate and audio signals.

Notes: Module A-183-9 is a simple power supply for up to four devices which can be powered via USB (e.g. keyboards, smartphones). An LED shows is the +5V are present.

The module has no USB function but provides only the +5V supply for USB devices.

A control LED shows if the +5V are present.

Note: The module requires an A-100 case with built in power supply A-100PSU3. Only this A-100 supply has the required +5V available. We do not recommend the usage of an older A-100 case with A-100PSU2 as this would require the +5V adapter A-100AD5 and the max. current would be limited to 100mA.

Notes: The Doepfer A-126-2exp is an expander for the A-126-2 Voltage Controlled Frequency Shifter.

It adds two outputs from the Dome filter (+45 and -45 degrees) as well as separate outputs from the ring modulators 1 and 2, and from the internal envelope generator. Furthermore, it offers dedicated outputs for Up and Down Shift, allowing the module to be patched in stereo.

*Note: The expander can only be used in conjunction with the module A-126-2.

HP : 2

Notes: The Doepfer A-126-2exp is an expander for the A-126-2 Voltage Controlled Frequency Shifter.

It adds two outputs from the Dome filter (+45 and -45 degrees) as well as separate outputs from the ring modulators 1 and 2, and from the internal envelope generator. Furthermore, it offers dedicated outputs for Up and Down Shift, allowing the module to be patched in stereo.

*Note: The expander can only be used in conjunction with the module A-126-2.

HP : 2

Notes: Module A-182-1 is a simple passive multi-connector similar to the multiples modules A-180-1/A-180-2. In contrast to modules A-180-1/2 each socket is equipped with a 3-position switch that allows to connect the corresponding socket to the internal bus #1 (left position), bus #2 (right position) or to turn the socket off (centre position).

Examples:

- All switches in left position or all switches in right position: 8-fold multiple

- Four switches in left position and four switches in right position: two 4-fold multiple

- X switches in left position, Y switches in right position and Z switches in centre position: two separate multiples with some sockets turned off

Notes: Module A-151 (Quad Sequential Switch) is like an electronic four-position rotary switch.

It includes trigger and reset inputs, four in / outputs, and a common out / input. Each time a pulse is received at the trigger input socket, the common out / input is connected to the next in / output. After the fourth in / output, the next trigger makes it step back to the first again, and so on. A positive pulse at the reset input switches the out / input immediately back to the first in / output (see Fig. 1). Voltages in the range -8V...+8V at the O/I resp. I/O sockets can be processed by the module.

Four LEDs indicate the active in / output (i.e. the on that is connected to the out / input at any particular time).

Notes: Module A-160 is a frequency divider for clock/trigger/gate signals, designed to be a source of lower frequencies, particularly for rhythm uses. The Trigger input will take clock signals from, e.g. an LFO, MIDI sync, or the gate from a MIDI-CV interface.

At the outputs, you have access to the sub-divided clock signals, from half the clock frequency down to 1/64. The low/high levels of the output signals are 0V and about +10V.

The A-160 also has a reset input. Whenever a reset signal is sensed, all outputs are set to zero, until the reset voltage disappears.

The Clock Divider can be used in combination with the A-161 Clock Sequencer to produce stepped sequences with a length of from one to eight events.

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).

Notes: Module A-151 (Quad Sequential Switch) is like an electronic four-position rotary switch.

It includes trigger and reset inputs, four in/outputs, and a common out/input. Each time a pulse is received at the trigger input socket, the common out/input is connected to the next in/output. After the fourth in/output, the next trigger makes it step back to the first again, and so on. A positive pulse at the reset input switches the out/input immediately back to the first in/output. Voltages in the range -8V...+8V at the O/I resp. I/O sockets can be processed by the module.

Four LED's indicate the active in/output (ie. the one that is connected to the out/input at any particular time).

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-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-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: 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-179-2 can be used to convert different illumination intensities into corresponding analog voltages and a gate signal derived from the analog voltage. It's the successor of the obsolete module A-179.
A light sensitive resistor (LDR) converts the illumination of the internal light sensor into a corresponding analog control voltage. The internal sensor is located at the front panel. Instead of the internal sensor a remote sensor can be connected via a standard patch cable to the module (ext.Sens. socket). An external sensor with a 2 m patch cable (A-100C200) is included. The external sensor is mounted on a small pc board which is equipped also with a 3.5 mm jack socket. The nut of the socket can also be used to mount the external sensor.

The module A-179 is similar to the Theremin module A-178 but uses the illumination intensity instead of the distance between hand and antenna for generating the analog voltage.
One can choose between passive control by covering/shading the sensor via hand or body, or active control by using e.g. a pocket lamp or flashlight. For this two versions of output voltages are available (CV Out + und CV Out -).

The module has these controls and in/outputs available:

ext. Sens.: by means of a standard patch cable the external sensor can be connected to this socket. In this case the internal sensor is turned off.

CV Offset: control to adjust the output voltage which is assigned to a certain illumination (e.g. 0V for complete darkness)

CV Level: control that is used to adjust the sensitivity of the generated output voltage (i.e. how much a certain difference in brightness affects the output voltage)

Gate Threshold: control that is used to adjust the threshold for the generation of the gate signal, an internal jumper is used to define if the gate signal is derived from the CV Out+ or CV Out- voltage.

CV Out+: positive control voltage output, increasing brighness causes the increase of the voltage at this output

CV Out+: negative control voltage output, increasing brighness causes the decrease of the voltage at this output

LED CV Out: bipolar LED (red/yellow) as display for the CV outputs

Gate: gate output with LED display

Applications:

controlling any voltage controlled parameter e.g. pitch or pulswidth of a VCO, filter frequency or resonance of a VCF, loudness of a VCA, time of an envelope generator, frequency of a VCLFO
triggering activities via gate with adjustable threshold, e.g. starting an envelope, starting/stopping a sequencer or any switching function (e.g. with A-150-1 or 151).
Conversion into MIDI control change messages is possible with the A-192-2.

Width: 4 HP / 20.0 mm
Depth: 30mm (measured from the rear side of the front panel)

Notes: ***B-STOCK: Item refurbished, repaired and in perfect working order.***


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-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-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-130-4 contains four linear VCAs with a common level control section for all four VCAs. It can be used for all applications of simultaneous amplitude/level control of up to four different audio or CV signals. A-130-4 is the replacement of the no longer available module A-132-2. Compared to the A-132-2 the width has been reduced from 8HP to 4HP.

The module has these controls and in/outputs available:

Control Man.: manual control of the amplification
Control CV: attenuator for the control voltage applied to socket CVo socket Input 1
Sockets In 1...4: VCA inputs 1...4
Sockets Out 1...4: VCA outputs 1...4

Application examples:

simultaneous amplitude/level control of up to four different audio or CV signals
polyphonic application 1: simultaneous control of the frequency modulation depth of 4 VCOs (Quad-LFO A-145-4 or Quad-VCLFO A-147-5 > A-130-4 > FM inputs A-111-4)
polyphonic application 2: simultaneous control of the pulsewidth modulation depth of 4 VCOs (Quad-LFO A-145-4 or Quad-VCLFO A-147-5 > A-130-4 > PWM inputs A-111-4)
simultaneous control of quadrophonic signals

Technical notes:

The maximum amplification for each VCA is about 1 ("Man." control fully CW). Even with an external control voltage applied to the CV input the maximum amplification is limited to 1.
The module is equipped with two internal connectors (pin headers with 4 pins each). Pin header #1 can be used to normalize the four inputs to other modules (e.g. Quad LFO A-145-4 or A-147-5, Quad ADSR A-143-2). Pin header #2 can be used to connect the four outputs to other modules.
The max. level at the VCA inputs without clipping/distortion is about 20Vpp or +/-10V.

Dimensions
4 HP
45 mm deep

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: 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-184-2 is the combination of two functions and planned primarily as an expansion module for VCOs or LFOs (e.g. A-110-1, A-110-2, A-145, A-147-2).

Triangle-to-Sine Waveshaper:

The upper section is a very precise triangle-to-sine converter (thanks to Tim Stinchcombe who recommended this circuit). It can be used to convert any triangle waveform into a (nearly) perfect sine. The converter is much better than the simple diode converter used in the A-110-1, A-111-1, A-145 and A-147-2. Two trimming potentiometers are used to optimize the sine shape. The converter should be assigned to one VCO or LFO because the trimming potentiometers have to be re-adjusted if the input level or DC offset of the input signal changes. If the trimming potentiometers are deliberately mis-adjusted it can be used also as a waveshaper for non-sine waveforms (e.g. sine-shaped at the top of the signal and a peak at the bottom, even voltage controlled by applying an additional voltage to the waveshaping circuit, "circuit-bending" notes will be available).

The waveform converter is DC coupled and can be used also for low frequencies (e.g. LFO triangle waves).

Voltage Controlled Crossfader:

The lower section is a voltage controlled crossfader. It has two inputs A and B. The two signals are mixed together with variable percentage. When the manual control CF is fully CCW only signal A appears at the CF Out socket. When the manual control CF is fully CW only signal B appears at the CF Out socket. In the centre position of the manual control both signal appear with the same level. In addition a control voltage input CV with attenuator is available to enable voltage control of the crossfade.

Two LEDs display the crossfading shares of input A and B.

The crossfader uses two high quality VCAs (SSM2164). Inputs and outputs are DC coupled. Consequently it can be used for audio signals and slowly varying control voltages as well.

The sockets of the upper section (triangle and sine) are normalled to the inputs A and B of the crossfader section. That way the crossfader is used to fade between triangle and sine of the VCO or LFO connected to the waveshaper. If other signals are plugged into the input sockets A and B these signals are used for crossfading.

The main application is to fade between two different waveforms of a VCO or LFO or two different VCF outputs. But the module can be used for any other signals too as the waveshaper and crossfader sections are independent apart from the normalled sockets.

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-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