Doepfer

Notes: A fully modular, Eurorack-format version of the excellent Dark Energy synth, the A-111-5 offers VCO, VCF, LFOs, VCA and envelope generator in a compact format. Brilliant value for a starter system.

Supplier's Notes:
Module A-111-5 is a complete monophonic synthesizer module that includes these components (modular version of Dark Energy):

VCO
Manual tune control (with an internal jumper the range can be set to ~ +/-1 half an octave or ~ +/-2.5 octaves)
Range switch -1 / 0 / +1 octave
Frequency range about 10Hz ... 12kHz - FM (frequency modulation) control with modulation source switch (LFO1 / off / ADSR)
Manual pulsewidth control for rectangle waveform
PWM control with modulation source switch (LFO2 / off / ADSR)
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)
External CV input for VCO frequency (1V/octave)
External CV input for external PWM of the rectangle - internal CV input for frequency (1V/octave) connected to the A-100 bus via jumper, the jumper can be used to interrupt this internal connection if not wanted

VCF
24 dB low pass
~ 12 octaves frequency range
Manual frequency control
Tracking switch half - off - full (internally connected to the external frequency CV input of the VCO, i.e. the VCF tracks to the VCO if the switch is set to "half" or "full" position)
XM: exponential FM (frequency modulation) control with modulation source switch (LFO2 / off / ADSR)
LM: linear FM (frequency modulation) control to modulate the VCF by the triangle of the VCO in a linear (!) manner
Manual resonance control (up to self oscillation)
External audio input (this signal is added to the VCO signal)
External CV input for filter frequency - 1V/octave tracking for usage of the VCF as a sine wave oscillator (not as precise as the VCO but much better than most of the other filters)
VCA
Manual amplitude control
AM (amplitude modulation) control with modulation source switch (LFO1 / off / ADSR)
External CV input for VCA amplitude - 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 VCA)
LFO1 and LFO2
Manual frequency control
Waveform switch (triangle / off / rectangle)
Range switch (low, audio, medium) - LED display (dual green/red color for positive/negative share of the signal)
The inverted LFO1 signal is available as an additional socket (to use the LFO1 signal for external modules)
An internal jumper can be used to select between the LFO1 signal or the inverted LFO1 signal

ADSR
Manual controls for Attack, Decay, Sustain, Release
Range switch (long, short, medium) - blue LED display
ADSR signal is available as an additional socket (to use the ADSR signal for external modules)
Gate input connected to the A-100 bus via jumper, the jumper can be used to interrupt this internal connection if not wanted

Remarks:
As the LFO frequencies can go up to moderate audio range (~ 5kHz) even audio FM effects of VCO (pitch and pulsewidth), VCF and ADSR are possible.

If the VCO is turned off (waveform switch = center position, pulsewidth control = fully CCW) and the VCF resonance is set to maximum the module can be used as a sine oscillator. The sine can be modulated in a linear manner from the triangle wave of the VCO and by LFO2 in an exponential manner at the same time !

From the factory the socket labelled "LFO1" outputs the inverted LFO1 signal. But as the module has several internal pin headers available even another signal may appear at this socket by changing the internal module patch. These six pin headers are available: LFO1 output, LFO2 output, ADSR output, inverter input, inverter output, output socket. The internal default patch is LFO1 -> inverter input, inverter output -> output socket (i.e. socket = inverted LFO1). But even another signal can be patched to this socket (e.g. inverted ADSR, non-inverted LFO1, inverted or non-inverted LFO2). It is also possible to add a blind panel next to the A-111-5 with a couple of sockets that are connected to the corresponding pins of the A-111-5 pc board. The in- and outputs of the VCO, VCF and VCA are not available as pin headers because the VCO, VCF and VCA are internally connected in the circuit which is used in this module.

Notes: Module A-101-8 is a 8-stage phase shifter which uses light-sensitive resistors (LDR) and is a replica of the Compact Phasing A manufactured by the company Schulte in the seventies. The actual phasing circuit is identical to the historic model. Only the illumination control of the LDRs is different: the A-101-8 uses LEDs to illuminate the LDRs, the historic model used incandescent miniature lamps. And the A-101-8 has no built-in LFO but can be controlled by any external control voltage source (e.g. LFO, ADSR, random, Theremin, ribbon controller, sequencer, midi). The phasing offset (i.e. the base value for the phase shifting) and the modulation depth of the external control signal can be adjusted separately. The Compact Phasing A had no offset control but only a depth control for the built-in LFO. Feedback and mixing ratio of the output signal are set by two controls. The audio input is equipped with an attenuator. The module has two audio outputs available (same as the historic model) and a visual display of the phase shifting.

The module has these controls and in/outputs available:

Control Man. : manual control of the phase shift offset (base value)

Control CV: attenuator for the signal applied to the CV socket

Control Feedb.: Feedback or Resonance (similar function as filter resonance/feedback/emphasis)

Control Mix: sets the mixing ratio between original and phase shift signal appearing at output 1

fully CCW: only the modified input signal appears at output 1 (see note below *)

center: a mixture between the modified input signal and the phase shift signal appears at output 1, that's the standard position for the classical phasing effect

fully CW: the pure phase shifted signal appears at output 1 (e.g. for vibrato effects)

Control Input Level: attenuator for signal applied to the In socket

Socket In: audio input

Socket CV: control voltage input

Socket Out 1: audio output 1 (mix signal)

Socket Out 2: audio output 2 (modified input signal)

LED: visual control of the phase shift

The module has some peculiarities (same as the historic model):

The input signal is processed at first by a pre-stage which outputs a "modified" input signal (*). This signal is not processed by the phase shift stages but is affected by the feedback setting. Only when feedback is set to zero this signal is identical to the input signal. Otherwise it contains feedback components.

This signal is output on socket Out 2.

When both output sockets Out 1 and Out 2 are used as stereo channels one obtains a spatial stereo sound effect.

The same signals is also used for the CCW position of the mix control. With mix control fully CCW the unmodified signal appears only if the feedback control is set to zero. Otherwise it contains feedback components.

The historic model had two audio inputs: one 5-pin DIN socket and a 1/4" jack socket. The DIN socket was intended for high-level line signals. When the 1/4" jack socket was used the amplification of the pre-stage increased by about 100. The 1/4" jack socket was intended for low level signals (e.g. electric guitars or microphones). For this feature the A-101-8 has an internal jumper that can be used to increase the amplification. As long as the module is used within the A-100 system usually the lower amplification is used to avoid distortion.

The 8 photo resistors and LEDs are assembled within an small lighproof box. In addition the pc boards are made of lighproof black material to avoid interfering light from other modules or the bus board.

Dimensions
4 HP
45 mm deep

Current Draw
30 mA +12V
30 mA -12V

Notes: Module A-147-4 is a dual voltage controlled LFO (Low Frequency Oscillator). Each LFO has the five waveforms triangle, sine, rising and falling sawtooth, as well as rectangle available. The rectangle output features manually adjustable pulsewidth and pulsewidth modulation by means of an external control voltage. The core waveform is triangle. The other waveforms are derived from triangle by means of waveform converters. The frequency of each LFO can be adjusted manually and modulated by means of an external control voltage with associated attenuator and polarity switch. By means of a jumper the basic frequency range of each LFO can selected: about 0.02 Hz (~ 50 seconds) ... 2.5kHz or about 0.0017 Hz(~ 600 seconds) ... 220Hz. That way each LFO can be used also as a VCO with a max. frequency of about 2.5kHz. Each LFO features a reset input which can be used to reset the triangle signal.

The module has these controls and in/outputs available:

Control F : manual control of the frequency, for each LFO the frequency range can be selected by means of a jumper from two values (see technical notes)

frequency coverage of control F in the high frequency range: about 0.075 Hz (~ 13 seconds) ... 1,4kHz

frequency coverage of control F in the low frequency range: about 0.007 Hz (~ 140 seconds) ... 125Hz

Control CV: attenuator for the signal applied to the CV socket, by means of a jumper a small positive voltage can be applied to the switching contact of the /CV/ socket, as long as no patch cable is connected to /CV/ socket the CV control then works as fine control for the frequency

Switch CV Pol.: polarity switch for the signal applied to the socket /CV/

Control PW/PM: combined control for manual and CV control of the rectangle pulsewidth:

when no patch cable is connected to socket /P/ the control is used to adjust the pulsewidth (PW) manually

when a patch cable is connected to socket /P/ the control works as attenuator for the external CV signal with a basic pulsewidth of 50:50.

Socket /CV/: frequency control voltage input, in the factory the module is adjusted so that the sensitivity of this input is exactly 1V/octave when the CV control is fully CW.

Socket /R/: reset input, according to the associated jumper the reset input is edge triggered or level controlled (see technical notes for details)

Socket /P/: pulsewidth control voltage input

Sockets with waveform symbol: output of the waveform in question (triangle, sine, rising and falling sawtooth, rectangle)

The output voltage ranges are about -5V ... +5V (10Vpp), except the rectangle output

For the rectangle output one can choose by means of a jumper if the range is about -5V ... +5V or 0...+10V.

LED: visual control of the LFO (triangle)

The inputs of the module are labelled with white characters on black background (in the text included into two slashes). The outputs are labelled with black characters.
Technical notes and special features:

The basic frequency range of each LFO can be selected by means of a jumper. The settings correspond to two different capacitor values for the VCO circuit. The relation between the two ranges is about 1:11. When the upper range is selected frequencies from about 0.02 Hz up to 2.5kHz can be generated. For the lower range the values are about 0.0017 Hz ... 220Hz. To obtain these full frequency ranges external control voltages are required. With the frequency control F only the frequencies mentioned above are possible.

Apart from that the range for the manual control F can be reduced to obtain a finer resolutuion. For this a jumper has to be removed. The range of control F is then reduced to about 1:4.5 only.

In the factory the starting voltage of the triangle output after a reset is adjusted to 0V, i.e. the triangle starts from 0V with the rising slope after a reset. By means of a trimming potentiometer the starting voltage can be adjusted to another value (e.g. to -5V).

Another jumper is used to set the reset behaviour to edge triggered or level controlled. When set to edge triggered the rising edge of reset signal is used for the reset (independent of the duration of the "high" state of the reset signal). When set to level controlled the triangle output remains at the starting voltage as long as the reset signal is "high". Only when the reset signal turns "low" the triangle starts.

Dimensions
8 HP
45 mm deep

Current Draw
80 mA +12V
70 mA -12V

Notes: Module A-118-2 generates the signals white noise, colored noise, continuous random voltage and stepped random voltage.

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 and Blue noise (low/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 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 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 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. Dual color LEDs are used to indicates the continuous and stepped random voltages.

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 und 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.

The level of the random voltage changes with the settings of the Blue and Red controls. Especially the Red control affects the random voltage level (which is derived by low pass filtering from the colored noise signal) because the Red control changes the share of the low frequencies in the colored noise signal. The effect of the Blue control is much smaller because it changes the share of the high frequencies in the colored noise signal which are filtered out by the low pass of the random circuitry.

Power consumption: 20mA at +12V and 20mA at -12V
Depth: 40mm
HP : 4

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: Theremin module for generating a variable control voltage by approaching/removing hand to/from an antenna. The distance range is about 30-40 cm. Additionally the module is equipped with a Gate output with adjustable threshold level. Controls/Inputs/Outputs: antenna input, offset (knob for zero adjust), 2 x CV out, 2 x LED (for CV control positive/negative and zero offset adjust).

To simulate the original Theremin two A-178, a VCO (e.g. A-110) and a linear VCA (e.g. A-130 or A-132) are required. But of course the A-178 can be used to control other functions in the A-100 (e.g. filter frequency, modulation depth and/or speed, tempo, attack/decay time and so on).

The CV output voltage of the A-178 can range - according to the setting of the front panel controls - from -10V...+10V. The gate output switches from 0V to about +10V.

Applications:

- Controlling any voltage controlled parameter of the A-100, e.g. pitch or pulsewidth (VCO A-110), loudness (VCA A-130/131/132), panorama (A-134), filter frequency or resonance (A-120/121/122/123), phasing (A-125), frequency shift (A-126), resonance peaks (A-127), envelope parameters (A-141/142), tempo (A-147)

- Triggering of A-100 activities via gate with adjustable threshold, e.g. starting an envelope (A-140/141/142), Start/Stop of a sequence (A-155), any switching function (A-150/151)

- Conversion into MIDI control change messages is possible with the A-192.

If two or more A-178 are used the distance between the modules/antennas should be at least 40-50 cm. Otherwise the antennas may affect each other.

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-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-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: Module A-171-2 is a voltage controlled slew limiter with a lot of additional features beyond a simple slew limiter. It's mostly a licensed copy of Ken Stones VCS which is in turn based on the Serge VCS.

Typical applications:

- VC Slew Limiter / VC Portamento / VC Low Pass Gate:

Cycle switch = off, no trigger signal applied to Trig socket: Voltage controlled Slew limiter or portamento generator: the signal applied to the signal input is "slewed". The slew up and down times are controlled manually by means of the Up and Down controls, the effect of the CV Up and CV Down control voltages are controlled by the CV Up and CV Down controls, in exponential mode these controls also affect the slew shape (see symbols at the CCW and CW positions of the controls).

If an audio signal is applied an short slew rates are chosen the module works as a simple VCF/VCA combo.

- A/D Envelope Generator / Pulse Delay / Subharmonic Generator:

Cycle switch = off, trigger signal applied to Trig socket, no input signal: Simple Attack/Decay envelope Generator, the rise and fall times are controlled like the slew up/down times above, including the shape of the falling/rising slope of the envelope, the exp. CV input can be used to change both attack and decay simultaneously.

At the End output a pulse appears as the end of the envelope is reached (less than about 20mV), this can be used as a pulse delay.

If a series of triggers are applied to the VCS faster than the total rise and fall times, the module will divide the incoming signal by a whole number. In the audio range the output will be the sub-harmonic series.

- VCLFO / VCO:

Cycle switch = on, no trigger signal applied to Trig socket, no input signal: Voltage controlled LFO/VCO, the rise and fall times of the waveform are controlled like the slew up/down times above, including the shape of the falling/rising slope
the exp. CV input can be used like the CV input of a VCO or VCLFO, the response is exponential but not exactly 1V/oct.

Notes: USB/MIDI to clock interface that allows for synchronizing clock-driven modules with the MIDI environment. It processes only the Clock, Start, Stop and Continue MIDI commands. It has several clock divider outputs, each one start, stop and reset outputs for controlling sequencers and also an interesting wait function. Input is either a 5-pin DIN socket or USB.

Notes: Module A-192-2 contains two independent CV/Gate-to-Midi/USB interfaces. For each of the two sub-units these inputs are available:

- Gate Input (min. +5V)
- CVN Input (defines the Midi note number), 1V/octave standard, range 0...+10V (i.e. 10 octaves)
- CVV Input (defines the velocity value assigned to the Midi note message), can be used alternatively for Midi volume (CC#7), range 0...+5V
- CVC Input (free assignable to any Midi control change number), range 0...+5V

For both sub-units a common CV Transpose input is available (1V/octave, range 0...+10V). The voltage applied to this input is added internally to CVN before the Midi note number is generated. It can be used e.g. to transpose two sequences simultaneously by one voltage.

How it works:

Whenever the rising edge of the Gate input is recognized a Midi note on message is generated. The note number corresponds to the sum of the voltages applied to the CVN input and the common CV Transpose Input that is present at the rising edge of the gate signal.

Notes: Module A-196 contains a so-called phase locked loop (PLL). The basic PLL system is shown in the sketch at the bottom of this page. A PLL consists of three parts: voltage-controlled oscillator (VCO), phase comparator (PC), and low-pass filter (LPF). All parts are normally connected to form a closed-loop frequency-feedback system.

This is how a PLL works: The output of the internal VCO (linear CV control, rectangle output) is compared with an external signal (e.g. the rectangle output of a A-110 VCO) in the so-called phase comparator (PC). The output of the phase comparator is a digital signal (low/high/tristate) that indicates if the frequency resp. phase difference of the two input signals is negative, zero or positive. The output of the phase comparator is processed by a low pass filter (LPF) to generate a smooth voltage that is used to control the frequency of the internal VCO. The 3 units VCO, PC and LPF form a feedback loop that works like this: The control voltage (output of the LPF) increases as long as the external frequency is higher than the frequency of the internal VCO und stops increasing when both frequencies become identical. The control voltage decreases as long as the external frequency is lower than the frequency of the internal VCO und stops decreasing when both frequencies become identical.

But there are some stumbling blocks: Different types of phase comparators with advantages and disadvantages can be made. Some phase comparators e.g. even lock at harmonics, i.e. if the two frequencies to be compared are integer multiples. But for some applications this can be used to create interesting effects. The A-196 contains 3 different types of phase comparators: PC1 is a simple exclusive OR, that even locks at harmonics. PC2 is a so-called RS flipflop and PC3 a more complex digital memory network. The user can select one of the three phase comparators with a 3-position switch. When PC2 is used a LED displays the "locked" state, i.e. when the frequency of the internal VCO is identical to the external frequency.

Special attention has to be directed to the frequency of the LPF. To obtain a smooth control voltage for the VCO the frequency of the LPF has to be much smaller than the lowest frequency of the internal or external audio signal. Otherwise the frequency of the internal VCO will jitter or wobble around the correct frequency. But for special effects this frequency jitter can be used intentionally. Example: frequencies in the range 50Hz...1kHz have to be processed with the PLL. Therefore the frequency of the LPF has to be about 10Hz or even less. Such a low frequency of the LPF causes a noticeable slew of the internal VCO. When the frequency of the external signal jumps e.g. between 500Hz and 1kHz it takes about 0.1 second until the internal VCO reaches the new frequency (like portamento). So one has to find a compromise between frequency jitter and portamento. But these remarks are valid only for the "ideal" working PLL. As the A-196 is used in a musical environment the "problems" and disadvantages with jitter and slew time lead to additional musical applications like portamento effects, wobbling frequencies or harmonic locking according to the type of frequency comparator and time constant of the PLL low pass filter. Instead of the internal manually controlled low pass filter the voltage controlled slew limiter A-171 can be used to obtain voltage control of this parameter. Normal audio filters (e.g. A-120, A-121) cannot be used for this job as the minimum frequency is to high (down to a few Hz or even less necessary) and the signal has to be DC coupled due to the low frequencies. Audio filters are normally AC coupled.

Another very important application of a PLL is frequency multiplication in combination with an external frequency divider. For this the output of the PLL-VCO is processed through an external frequency divider (e.g. A-163, A-160, A-161, A-115) before it is fed to In1 of the phase comparator. In this case the frequency of the PLL-VCO will be a multiple of the master frequency. E.g. if the A-163 is used and adjusted to dividing factor 5 the frequency of the PLL-VCO will be 5 times the frequency of the master VCO. Consequently, frequency division (A-163) leads to frequency multiplication with the PLL circuit. In combination with the PLL low pass frequency several effects can be realized (frequency multiplication with portamento or wobbling). The frequency multiplication can even be used to drive a graphic VCO. If your graphic VCO e.g. has 8 steps (e.g. A-155) and you use a frequency divider with factor 8 in the PLL feedback the output of the graphic VCO has the same frequency as the master VCO. Another application is the generation of pseudo-harmonics (not real harmonics as only rectangle waves are available) or clock generation for switched-capacitor filters.

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, 8HP, constructed from anodised aluminium, silver.

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

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-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-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: 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: 120cm
- Blue finish

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

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: 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. Green 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: 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: 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: 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: Module A-174-4 modules outputs three control voltages generated by a spring-loaded X/Y cross potentiometer (so-called joy stick) and a Gate signal. The control voltages for X and Y are controlled by the X and Y position of the joystick in the usual way. The third control voltage Z is controlled by the rotation of the spring-loaded joystick knob. The Gate signal is generated by a button at the center/top of the joystick knob.

For each control voltage the non-inverted signal (X, Y, Z) as well as the inverted signal with adjustable offset (-X+XO, -Y+YO, -Z+ZO) are available. The generic joystick control voltages are bipolar, i.e. they range from typ. -5V (lowest position) via 0V (center position) to typ. +5V (highest position). The "Overlap" switches can be used to add a fixed offset voltage of typ. +5V to the non-inverting output in question so that the output voltage range changes to typ. 0...+10V (rather than -5...+5V). That's necessary if e.g. a VCA has to be controlled, which requires a pure positive control voltage range. The switches are named "overlap" because they allow the overlapping of the non-inverting CV output (X, Y, Z) with the inverting output (-X+XO, -Y+YO, -Z+ZO) for crossfading applications. With the overlap switch "on" and appropriate setting of the offset control it's possible to obtain a control voltage range of 0...+10V for the non-inverting output and +10V...0V (i.e. same range but opposite direction) for the inverting output.

The offset voltages which are added to the inverting outputs can be adjusted by means of three small potentiometers. That way different kinds of control voltage ranges are possible, e.g.
-5V ... +5V for the non-inverting output and +5V ... -5V for the inverting output ( Overlap = off, Offset = 0)
0 ... +10V for the non-inverting output and +10V ... 0V for the inverting output ( Overlap = on, Offset = max)
-5V ... +5V for the non-inverting output and +10V ... 0V for the inverting output ( Overlap = off, Offset = max)
0 ... +10V for the non-inverting output and +5V ... -5V for the inverting output ( Overlap = on, Offset = 0)
On top of this the four quadrant voltages Q1, Q2, Q3 and Q4 are available. A quadrant voltage becomes positive when the joystick is positioned in the quadrant in question.
Each CV output is equipped with an LED that displays the present voltage.

Because of the construction height of the joystick (about 7 cm) the module cannot be installed into the cases A-100P6, A-100P9, A-100PMS6, A-100PMS9 and A-100PMS12 during transportation as the depth of the case cover is not sufficient. Into the base cases A-100PB and A-100PMB as well as in all other cases without cover the module can be installed without problems.

HP : 12

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: 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-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 A152 is a very useful switching and T&H module. It combines a voltage addressed 1-to-8 multiplexer and 8 fold T&H that can be used as kind of an analogue shift register too. The active in/output is displayed by a LED. The digital output of the currently addressed step outputs "high". The remaining digital outputs are low.

Instead of voltage control even clock/reset controlled addressing of the active step is possible. The rising edge of each clock signal causes an advance to the next state. The rising edge of the reset signal resets to step 1.

The sum of the voltages coming from the manual Address control and the CV input define the currently addressed step of the 3 sub-devices. If the module is controlled by clock and reset the control voltage has to remain unchanged as the CV control has priority over the clock/reset control (e.g. simply turn the CV control fully counter-clockwise and do not touch the Address control knob).

Sub-device #1 is the bidirectional 8-fold multiplexer (kind of an electronical 8-fold rotary switch). Bidirectional means that it works into both directions like a mechanical rotary switch: the common socket may work as an output that is connected to one of the 8 inputs that are e.g. connected to modulation or audio sources. But the common socket may even function as input. In this case the signal applied to the common socket is output to the currently addressed single socket. The voltage range of the in/outputs to be switched is the full A-100 voltage range -12V....+12V. All A-100 signals can be switched without any restrictions.

Sub-device #2 is the addressed 8-fold T&H. The signal at the common T&H input is connected to the addressed T&H output. As soon as a new output is addressed the last voltage is stored at the output (Track&Hold function). The T&H section of the A-152 allows the emulation of the "toggling T&H" function of the Buchla module 266 "Source of Uncertainty". Only the first two T&H outputs of the A-152 are required for this application. This unit can be used also as kind of an analogue (shift) register. The difference to a "real" analogue shift register is that the sampled output voltages are not shifted to the next output but remain allocated to the same output. But in some cases (e.g. controlling the pitch of 3 VCOs by 3 output voltages of the A-152) the result is the same.

Sub-device #3 is the digital output section. The digital output of the currently addressed turns to "high". All other digital outputs are low. The digital outputs can be used to trigger e.g. envelope generators or to control the reset input in the clocked mode to reduce the number of addressed stages.

Notes: Module A-160-5 is a voltage controlled clock multiplier. The incoming clock signal (socket Clock In) is multiplied by a factor that depends upon the control voltage on socket CV In (0...+5V) and the position of the Mode switch. The multiplied clock signal is available at the socket Clock Out. According to the position of the Mode switch different clock multiplying factors are assigned to the control voltage. With 0V CV no clock output is generated. This state is indicated by "all LEDs off". With increasing CV integer factors (left position of the mode switch), power of two factors (middle position) or a mix of both (right position) are obtained. Nine LEDs are used to show the currently selected multiplying factor. In addition two LEDs are used to display the incoming and outgoing clock signal.

A manual control is used to adjust the clock multiplication factor manually without the need of an external control voltage. The voltage generated by this control ("Manual") is normalled to the CV In socket. As long as no plug is inserted into the CV In socket the clock multiplication factor is adjusted by means of the manual control knob and displayed by the LEDs. For dynamic applications (like the ratcheting function described below) the manually generated CV is overwritten by the external CV which has to be fed into the CV In socket.

The module can be used for all kind of clock multiplying applications. One important example is the generation of so-called ratcheting sequences. The band Tangerine Dream is famous for this kind of sequences. A normal sequencer generates only one gate signal per step. A ratcheting sequence may have also more than one gate pulses per step. This function can be obtained by using the A-160-5: one CV output of the sequencer is used to define the number of gate pulses per step. If the control of the step in question is fully CCW the generated CV is 0V and no gate signal is generated (mute of the step). When the control of the step in question is turned clockwise one, two or more gate pulses are generated depending upon the position of the mode switch and the voltage generated by the CV at this step.

Technical note: Due to the nature of clock multiplying it takes a few input clock pulses until the clock output is stable. One has to average a few input clock pulses to generate the multiplied clock output signal. Even when the input clock frequency changes it will take a few cycles until the output clock signal is correct as the module cannot foresee the future of the clock input signal. The generated clock output signal is derived from the last few cycles of the clock input signal. Consequently the module should be driven only by a clock signal with constant or slowly changing frequency.

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: 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: A-180-9 is another simple but useful tool. It can be used to connect up to 14 signals between different cases by means of standard network cables (RJ45). These cables are available all over world smoothly in different lengths and colours. From the factory two black network cables with 0.5 m length are enclosed.

The upper network connector is wired to the eight sockets 1-8, the lower to the six sockets A-F. That way it's possible to pre-patch different cases and connect signals, that are required in all cases (e.g. clock, start/stop, master CV) by means of one or two cables only instead of 14 individual patch cables. When only eight signals are required only the upper network connector is required and the sockets 1-8 are used. When more than eight signals have to be patched both network connectors have to be used. It's also possible to wire the upper and lower network to different cases (i.e. signals 1-8 to external case #1 and signals A-F to external case#2).

The module is fully passive (no power supply required) and simply wires the 14 sockets to 14 pins of the network connectors.

The A-180-9 comes in pairs for combining two modular systems.

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-160-2 is an enhanced version of the standard clock divider A-160. The module is a frequency divider for clock/trigger/gate signals, designed to be a source of lower frequencies, particularly for rhythm uses. The Clock input will take any digital signal from, eg. LFO, MIDI sync, or the gate from a MIDI-CV interface. At the outputs, you have access to three sets of seven different sub-divided clock signals, from half the clock frequency down to 1/128. The low/high levels of the output signals are 0V and about +10V.

The A-160-2 also has a reset input. Whenever a reset signal is sensed, all outputs are set to certain levels which depend upon the selected mode.

These are the most important features of the module:

Three different sets of dividing factors, selected by a three-position switch at the front panel:
- Power of two: 2, 4, 8, 16, 32, 64, 128
- Prime numbers: 2, 3, 5, 7, 11, 13, 17
- Integer: 2, 3, 4, 5, 6, 7, 8

Two output modes, selected by a two-position switch at the front panel:
- Gate mode: outputs act like the outputs of typical binary dividers
- Trigger mode: in this mode the outputs are AND-wired with the clock signal (i.e. the clock pulsewidth affects the pulsewidth of the outputs)
- Clock edge type selected by a jumper on the pc board:
- Positive: the rising edge of the clock signal triggers the state change of the outputs
- Negative: the falling edge of the clock signal triggers the state change of the outputs

Reset behaviour by two jumpers on the pc board:
- Level triggered: the level at the Reset input triggers the Reset
- Edge triggered: the edge of the signal at the Reset input triggers the Reset
- Positive: a high level (> 2.5V) or the rising edge at the Reset input triggers the Reset
- Negative: a low level (< 1 V) or the falling edge at the Reset input triggers the Reset

Output polarity selected by a jumper on the pc board:
- Positive: non-inverted outputs
- Negative: all seven outputs are inverted

Width: 4HP / 20mm
Depth: 35mm (Measured from the rear side of the front panel)
Current: +12V: +50mA, -12V: -0mA