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Notes: The MCV4 is a budget-priced MIDI-to-CV interface to control vintage monophonic synthesizers via MIDI. The MCV4 is provided with 4 analog control voltage outputs (CV1-4) and one gate/trigger output.

MIDI channel, reference note for CV1 (this is the MIDI note corresponding to 0V of CV1 and thus the lowest possible note of the analog synthesizer connected to MCV4) and the controller no. for CV4 are adjusted via learn function. For this the learn button must be pressed and the required MIDI messages sent from the MIDI controlling device (MIDI synthesizer, keyboard, sequencer). The other parameters (retrigger, trigger polarity and assign mode) are adjusted in learn mode via program-change messages.

The Hz/V mode available in the predecessor model MCV1 is not available with the MCV4 because of the many problems occuring with the non-linear Hz/V characteristic. But some synthesizers normally using Hz/V can be be controlled with V/Oct (e.g. Korg MS10/MS20, details you may find in the MCV4 user's guide).

If you want to use all 4 analog control voltages, you need 2 special cables with a stereo 1/4" jack plug on one end (MCV4 side) and 2 mon 1/4" jack plugs on the other (synthesizer side). You may get such cables from your local dealer but Doepfer also offer such a cable (MCV4 cable 1/4" stereo, 2 x 1/4" mono). If you need it Doepfer recommend to order it together with the MCV4.

Notes: Dark Time is an 2 x8 steps analog sequencer with CV/Gate, USB and Midi interface. It is planned in the first place as an add-on for the Dark Energy but may be used even in combination with other Midi, USB or CV/Gate equipment too.

Features overview

two rows with 8 controls each
for each step:
- rotary control (same knob type as Dark Energy)
- red LED
- three-position switch On/Off/Skip
On = trigger signal is active for this step
Off = no trigger for this step
Skip = step is skipped
- three-position switch Stop/Continue/Jump
Stop = sequence stops here
Continue = sequence continues
Jump/Reset:
If only one of the 16 toggle switches is in the Jump position a Reset is carried out (i.e. sequence jumps to stage 1)
If two or more of the switches are in the Jump position the sequence jumps to the next step with the switch in the Jump position and then continues from this position (until another step with the switch in the Jump position is reached and then the same procedure is carried out again)
several operating modes:
1x16 (i.e. the two rows are daisy-chained)
2x8 (i.e. both rows run in parallel)
1-8 Combi (lower row set individual gate lenght of the upper row)
several running directions:
forward
backward
random
CV scaling: 1V/Octave standard (note: not suitable to control devices with Hz/V scale !)
several voltage / tuning ranges: 1V, 2V, 5V (corresponding to 1/2/5 octaves)
gate voltage 0/+5V (please refer to the remarks below concerning devices with S-Trigger or Korg MS10/MS20)
for units manufactured later than early 2012 (from serial number 120240) the output voltage for Gate/Clock/Reset/Start-Stop can be set to +12V by means of an internal jumper (the corresponding interface boards are marked V2/2011 or V3/2012). The following document describes the modification procedure in detail: Dark_Time_12V_Gate.pdf
if you own a unit manufactured before 2012 (serial number 120239 or less) the following technical document describes how to modify the unit for +12V level of the Gate/Clock/Reset/Start-Stop outputs: Dark_Time_12V_and_5V_Gate_Voltage_Modifikation.pdf
quantization on/off/custom scale (custom scale not yet available in the first firmware version)
when quantization is "off" the resolution is still 10 bit (i.e. 1024 steps over the full rotating range of each potentiometer), from this the term "quantization off" is not fully correct, with quantization "on" the resolution is 13/25/61 steps for 1/2/5 octaves
transpose via switch (-1/0/+1 octave), Midi/USB or external CV input
timing control, selected by a three position switch:
internal via built-in clock oscillator with frequency and pulsewidth controls
external via Midi/USB
external via analog clock/start/stop
analog interface for CV/gate/clock/Start-Stop (inputs and outputs, monophonic 3.5 mm miniature jack sockets)
Midi interface
USB interface (power supply via USB is not possible)
optically adapted to Dark Energy (same knobs, same depth and height, same wooden side plates and so on)
Powered via external power supply (12V AC/min. 400mA) for 230V
powering the device via USB is not possible, because the analog circuits require a dual voltage (+/-12V).
Additional remarks and specs:

for devices with S-Trigger inputs (e.g. Moog) or the Korg synthesizers MS-10/MS-20 a special S-Trig cable is required to connect the gate output of the Dark Time to the Gate/S-Trig input of the synth, details on the FAQ page of our website. You find the price of the special cable in our price list in the accessories section.

Dark Time cannot be used to control synthesizers which use the Hz/V standard for the pitch CV (unless the quantization of the Dark Time is not used). Only for the Korg MS-10 and MS-20 there is a solution to use 1V/Oct control voltage. A corresponding note can be found on our FAQ page: Controlling Synthesizers with Hz/V standard

Distance between the knobs (center - center): ~ 25 mm, diameter of the knobs: ~ 16 mm

Distance between the toggle switches (center - center): ~ 12.5 mm

Distance between knobs and switches (center - center): ~ 20 mm

The metal case is made of 1 mm steel, black coated with white printing

Overall dimensions: about 248 x 145 x 75 mm

Dimension of the metal case only (without side plates and knobs): about 223 x 135 x 55 mm

Side plates dimensions: about 145 x 65 x 12.5 mm (same as Dark Energy)

Weight: about 1.5 kg (without power supply)

The wooden side plates can be removed if desired. They are mounted by means of two screws to the metal box. The holes in the metal box can be used also to mount several devices together (e.g. with common wooden side plates on both ends) or to mount the Dark Time to one or two Dark Energy.

The device can be positioned horizontal (desk top) or vertical

These parts are included: power supply (12V AC/min. 400mA) for 230V mains voltage with European mains plug, one USB cable (type A-B, 2 m length) and four A-100 patch cables

For the power supply a low voltage DC socket with 5.5 mm outer diameter and 2.1 mm inner diameter is used (even 2.5 mm will work)

Powering the device via USB is not possible, because the analog circuits require a dual voltage (+/-12V).

Notes: Module A-174-4 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.

Important note:
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. Doepfer are close to finding a solution for this problem.

HP : 12

Notes: Mix four stereo signals with CV control over levels. Doepfer's usual great value and user-friendly approach make this a great choice at an excellent price point.

Supplier notes:
A-135-3 is a is a voltage controlled stereo mixer with four inputs. Behind a front panel with 8 HP only eight linear VCAs (voltage controlled amplifiers) and the mixer based on the VCAs are available.

Controls, Inputs and Functions of each input:

Level (manual control of the VCA amplification), small rubberized knob (L1...L4)

Control voltage input with associated attenuator (CV 1...4), 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 left/right (InL 1...4 / InR 1...4)

The signal inputs are 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 sum of the left and right signals appear at the sockets Out L and Out R. The maximal amplification is about 0.5 to avoid clipping at the mixer outputs (otherwise the outputs may distort with 15Vpp signals at each signal input and full amplifications). If another maximal amplification (e.g. 1) is required two resistors have to be replaced.

All inputs and outputs are DC coupled. Consequently the module can be used to process both audio and control voltages.

Additional technical specification for each VCA (based on the specifications of the VCA circuits CEM3360/AS3360 used in the module):
Crosstalk between two channels: better than - 80dB
Signal attenuation at 0V CV: better than -80dB
Total harmonic distortion: typ. 1%
Control voltage feedthrough: max. 15mV

HP : 8

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: 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-183-4 is a fourfold level shifter. A level shifter is required if the level of a digital control signal has to be increased or decreased. A typical application is the conversion of a gate, trigger or clock signal with +5V voltage level (tolerance range +2...+5V) to +12 voltage level. The output voltage level can be set by means of a jumper to +12V or +5V. The factory setting is +12V. But it can be changed to convert also a higher to a lower level (e.g. +12V to +5V). But this application is required rarely. The output level setting by means of the jumper is global, i.e. it is valid for all four units and cannot be set individually for each unit. The four output signals are displayed by means of LEDs.

The outputs and inputs of the four sub-units are normalled via the switching contacts of the input sockets, i.e. the output signal of the upper unit is used as input signal of the unit below provided that no patch cable is inserted into the input socket of the lower unit. That way the module can be used also as clock/trigger/gate buffer or buffered multiple for digital signals. For this the signal that has to be buffered is connected to input 1. The buffered (and possible level shifted) signal appears then at all four outputs.
Voltage thresholds for the input voltages:
voltages below +0,8 V are treated as "low"
voltages above +3 V are treated as "high"

Typical applications:

Converting the levels of digital control signals (e.g. gate, trigger, clock) to another voltage level (+12V or +5V)
buffering and duplicating digital control signals (e.g. gate, trigger, clock)

Important note: the module cannot be used for analog signals.

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

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

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

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

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

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-121-3 is functionally nearly identical to module A-121-2. Only the distances between the controls and sockets are smaller and rubberized, small rotary knobs are used. Therefore the front panel width is only 4HP compared to 8HP of the A-121-2. In the first place it is planned for applications where only limited space is available. The only functional difference compared to the A-121-2 is the missing attenuator for the resonance CV input CQ.

These are the most important features of the module:

- Voltage-controlled multi-mode filter with a cut-off slope of -12 dB / octave (identical to the filter of the Dark Energy II/III but has been expanded by the voltage controlled resonance feature)
- Four simultaneous outputs are available, each with different characteristics: low-pass (LP), high-pass (HP), band-pass (BP) and notch (N)
- Manual control Frequ. for the cut-off frequency of the filter (the cut-off frequency determines the point at which the respective filter effect appears)
- Two inputs for frequency control by means of external control voltages (frequency modulation, e.g. by ADSR or LFO):
- Control voltage input CV1 without attenuator, about 1V/octave sensitivity
- Control voltage input CV2 with attenuator FCV2 for the adjustment of the modulation depth of input CV2
- Frequency range about 10Hz ... 20kHz
- Manual control Q for the resonance of the filter
- Control voltage input CQ without attenuator for voltage control of the resonance
- Resonance up to self-oscillation, in which case the module will behave like a sine wave oscillator even without audio input signal
- Audio input In with attenuator Level for the adjustment of the filter input level (beyond about pos. 5 clipping/distortion occurs with typical A-100 audio levels)

Notes: Module A-138i is a four channel mixer with an additional mute switch for each input. On top of that it is equipped with two types of single outputs and a dual mix output. All inputs and outputs are DC coupled. Consequently the VCAs can be used to mix both audio and control voltages.

Each input is - apart from the mute switch - equipped with the usual attenuator.

The single outputs offer the attenuated and possibly muted signal of the channel in question. Two version of single outputs are available:

Single Output A: If a plug is inserted into the single output "A" socket the channel in question is removed from the sum signal.

Single Output B: If a plug is inserted into the single output "B" socket the channel in question is not removed from the sum signal. This type of single outputs is available only for the channels 1 and 2.

The output is twice available (two sockets, hard-wired like a multiple).

The distances between the controls and sockets are smaller as for the standard A-100 modules and rubberized small-sized knobs are used. In return the front panel has 6 HP width only. The module is primarily planned for applications where only limited space is available.

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: 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: A-111-4 contains four precision VCOs and has individual controls, inputs and outputs for each VCO available as well as a common control and output unit. After all the A-111-4 is very similar to four A-111-3 without LFO mode but built in output mixers for the three waveforms, and a master unit for all four VCOs.

Controls, inputs and outputs for each of the four VCOs:

- 1V/Octave CV input
- Octave switch (+1 / 0 / -1 octave)
- Tune control (range internally adjustable by jumpers: ~ 2 semitones / ~ 1 octave / ~ 4 octaves)
- Modulation CV input
- Modulation destination: Upper position: exponential frequency modulation (XM) / Lower position: linear frequency modulation (LM) or pulsewidth modulation of the rectangle (PM), selectable via internal jumper
- Frequency Modulation (FM) or Pulsewidth Modulation of the rectangle (PWM)
- Modulation intensity
- Triangle output
- Sawtooth output
- Rectangle output (about 50% without external PWM)
- Sync input (hard or soft sync internally selectable via jumper, CEM3340 hard sync type)
- CEM3340 based VCO (triangle core)
- Each VCO has it's own separate internal +/- power supply for each for best stability and the prevention of unwanted synchronisation of the VCOs

Controls, inputs and outputs of the master section:

- 1V/Octave CV input
- Octave switch (+1 / 0 / -1 octave)
- Tune control (range internally adjustable by jumpers: 2 semitones / 1 octave / 4 octaves)
- Frequency Modulation CV input (FM)
- FM intensity
- Triangle sum output
- Sawtooth sum output
- Rectangle sum output
- As soon as the single waveform output of a VCO is patched this waveform of the VCO in question is removed from the sum (this function can be turned off for each single output socket by means of solder bridges on the pc board, i.e. the sum contains then all signals independent of the patching of the single output)
- CV output (outputs the sum CV that is used to control all four VCOs)
- 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)

Typical applications:

- Fat sounding monophonic VCO with the possibility to adjust any intervals
- Paraphonic patches in combination with the polyphonic CV interface A-190-5 (all four VCOs processed by one VCF/VCA)
- Full polyphonic patches in combination with the polyphonic CV interface A-190-5 and four complete VCF/VCA sections
- Complex VCO patches with up to four VCOs by means of the frequency modulation features (exponential an linear) and the sync functions

Notes: Module A-145 is a low frequency oscillator, which produces cyclical control voltages in a very wide range of frequencies. Five waveforms are available: sawtooth, inverted sawtooth, triangle, sine and square wave.

The LFO can be used as a modulation source for any number of modules - for instance modulating the pulse width or frequency of a VCO, modulation of the cut-off frequency of a VCF, or amplitude modulation with a VCA.

A three-way switch lets you select three frequency ranges, spanning from one cycle every several minutes at the lowest, to moderate audio frequency at the highest (about 4-5 kHz).

The LFO signal can also be synchronised, via the reset input.

Notes: Module A-138 is a four channel mixer, which can be used with either control voltages or audio signals. Each of the four inputs has an attenuator, and there's a master attenuator, so that the mixer can be used at the end of the audio chain - i.e. it can be used to interface directly with an external mixer, amplifier, etc.

The A-138a version features potentiometers with linear response, so especially suitable for control voltage mixing.

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

Dimensions
2 HP
18 mm deep

Current Draw
Module does not draw current

Notes: The A-139-2 is a headphone amplifier module with two mono inputs and a stereo headphone output. It can be used for driving small loudspeakers, LED strips, small magnets etc.

- Two-channel headphone amplifier
- Two audio inputs with level controls
- Input 1 is normalled to Input 2
- Common loudness/master level control
- Headphone output (stereo 1/4" jack socket)
- Max. output power ~ 2 W per channel (@ 8 Ohm load)
- DC coupled inputs and outputs (i.e. also useful for other applications like small loudspeakers, lamps, LEDs, magnets, motors - provided that the power is sufficient)

Notes: Module A-140-1 is an envelope generator, and, since it puts out control voltages, counts as one of the modulation devices in a modular system. As soon as the gate input receives sufficient voltage, the ADSR generates a variable voltage, changing in time, called an envelope. This varying voltage is output in normal (positive) and inverted form, and can be used, eg. for voltage controlled modulation of a VCO, VCF, or VCA, or for processing other modules' inputs and outputs.

The shape of the envelope is governed by four parameters: Attack, Decay, Sustain and Release.

The envelope is started (triggered) by a gate signal either from the INT.GATE voltage on the system bus, or, if a signal is put into it, from the gate input socket.

The envelope can also be re-triggered, i.e. start from scratch again, each time a trigger signal is sensed at the Retrig. input socket, when the gate is still open.

Module A-140 has available a three-position toggle switch to select one of three time ranges. The time ratios for the three ranges are about 1 : 20 : 1000. The absolute Attack times are about:

20uS ... 100ms (switch position L)
400uS ... 2s (switch position M)
20ms ... 120s (switch position H)
The Decay and Release times are about 3-4 times more. Because of the exponential slope and the gradual asymptotic approach to the zero level the exact specification of the decay and real times is a bit difficult.

The voltage ranges of the ADSR outputs are about 0 ... +8V for the two normal outputs and 0 ... -8V for the inverted output.

In combination with the Comparator module A-167 a free-running "ADSR-LFO" can be realized.

Notes: The A-141-2 module is an ADSR envelope generator with voltage controlled attack, decay, sustain and release parameters. Other features include LFO functionality as well as digital end-of-attack and end-of-release outputs. Besides positive and inverted outputs there is an output with voltage controlled amplitude available.

Attack, Decay, Sustain and Release parameters of the A-141-2 can be adjusted manually as well as via control voltages. The CV inputs come equipped with attenuators. In addition, a Comm-CV socket was implemented. Control voltages fed to this input influence all time parameters (A, D and R) simultaneously. Thus, it is possible to make high pitched notes shorter and more percussive. - Just like the behaviour of many acoustic instruments. The time range of the envelope goes from 50 microseconds to six seconds. Using a toggle switch, it is possible to increase these values by a factor of ten (500 us to 60 s) or a factor of hundred (5 ms to 10 min). To activate the envelope, there are gate and retrigger inputs.

The A-141-2 is equipped with a normal and an inverted output. Both connectors work with a fixed level. Furthermore, there is a third, variable output. Here, before reaching the out socket, the envelope signal is fed to a voltage controlled VCA. - Perfect for velocity CV signals. A jumper on the circuit board allows you to choose between a unipolar and a bipolar mode of operation. Other jumpers make it possible to normalize the CV inputs.

Last but not least, there are two digital outputs called EOA and EOR, which emit a gate signal after the attack respectively release phase. This is useful for delayed triggering of other envelopes. By connecting EOA or EOR output to the gate input, you can make the A-141-2 oscillate like a LFO. Adjustments to the envelope times change the frequency and waveform. If you connect the Attack CV input to the inverted output or the Decay respectively Release CV input to the normal output, you can alter the curve characteristics.

Notes: The A-141-2 module is an ADSR envelope generator with voltage controlled attack, decay, sustain and release parameters. Other features include LFO functionality as well as digital end-of-attack and end-of-release outputs. Besides positive and inverted outputs there is an output with voltage controlled amplitude available.

Attack, Decay, Sustain and Release parameters of the A-141-2 can be adjusted manually as well as via control voltages. The CV inputs come equipped with attenuators. In addition, a Comm-CV socket was implemented. Control voltages fed to this input influence all time parameters (A, D and R) simultaneously. Thus, it is possible to make high pitched notes shorter and more percussive. - Just like the behaviour of many acoustic instruments. The time range of the envelope goes from 50 microseconds to six seconds. Using a toggle switch, it is possible to increase these values by a factor of ten (500 us to 60 s) or a factor of hundred (5 ms to 10 min). To activate the envelope, there are gate and retrigger inputs.

The A-141-2 is equipped with a normal and an inverted output. Both connectors work with a fixed level. Furthermore, there is a third, variable output. Here, before reaching the out socket, the envelope signal is fed to a voltage controlled VCA. - Perfect for velocity CV signals. A jumper on the circuit board allows you to choose between a unipolar and a bipolar mode of operation. Other jumpers make it possible to normalize the CV inputs.

Last but not least, there are two digital outputs called EOA and EOR, which emit a gate signal after the attack respectively release phase. This is useful for delayed triggering of other envelopes. By connecting EOA or EOR output to the gate input, you can make the A-141-2 oscillate like a LFO. Adjustments to the envelope times change the frequency and waveform. If you connect the Attack CV input to the inverted output or the Decay respectively Release CV input to the normal output, you can alter the curve characteristics.

Notes: Module A-142-1 is a voltage controlled envelope generator. The only time parameter is decay (like TB303). Decay may be adjusted manually and via voltage control input (with attenuator). The envelope output is displayed with LED control. Additionally from the envelope signal a Gate signal and an inverse Gate signal with adjustable threshold is derived. LED control for Gate output. Thus one obtains a voltage controlled Gate additionally or alternatively to the envelope signal with voltage controlled duration.

The attack time is fixed to about 0.2 ms, the shortest decay time is about 2 ms. By changing the value of a capacitor the shortest time can be modified (details can be found here: A100_Capacitors.htm).

Typical applications: dynamic control of decay e.g. in combination with the Analog/Trigger Sequencer A-155, voltage controlled trigger delay functions (like A-162, but voltage controlled).

Notes: Module A-142-4 contains four simple envelope generators. The only time parameter is Decay and can be adjusted manually by means of the Dec. control in the range 2 ms ... 2 seconds. The attack time can be adjusted internally by means of a separate trimming potentiometer for each sub-unit in the range 1 ms ... 15 ms. The factory setting is about 3 ms. This is the attack time of the TB303. Each envelope output has a LED control available. The trigger inputs are normalled (1 -> 2 -> 3 -> 4).

Suggestions for modifications:

Each sub-unit has a pin header with two pins available. When the two pins are shortened (e.g. by means of a jumper or a toggle switch connected to the two pins) the corresponding sub-unit changes to a loop mode. In this mode the unit is triggered by itself like an LFO..

By changing the value of a capacitor the time range can be modified (e.g. 0.2 ms ... 0.2 seconds or 20 ms ... 20 seconds)

Notes: Module A-143-1 is a complex envelope generator that consists of Attack/Decay generators. For the complex envelope generator the four units are daisy-chained, i.e. the preceding unit triggers the following unit. The four units can be used even as four separate AD generators (switch position AD) or AD-type LFOs (switch position).

Details: Module A-143-1 contains four separate attack/decay type envelope generators. Each unit can be switched into a free running mode (LFO mode). The LFO mode differs in several points from a regular LFO (like A-145, A-146 or A-147): The slopes are exponential - in contrast to linear slopes of a normal LFO, and the frequency is defined by both controls. The attack control defines the time of the rising slope, the decay control the falling slope.

Each unit has available a comparator that compares the AD output voltage with a manually adjustable threshold and switches the corresponding comparator output (Cp 1...4) to "high" as soon as the AD output voltage goes in the decay phase below this value. The comparator output is normalled to the trigger input of the next stage via the switching contact of the trigger input socket. Consequently the first unit triggers the second, the second triggers the third and so on.

Each AD generator is equipped with a Polarizer (look at the Voltage Controlled Polarizer A-133 concerning details about the polarizer function) and a mixer that adds up all polarizer outputs. This allows to add up all AD/LFO output signals inverting or non-inverting with adjustable level to the mix output. Additionally a single output (Env 1...4) is available for each unit.

If the trigger input of unit 1 is controlled by a normal gate signal (e.g. from a keyboard resp. MIDI-to-CV/Gate interface) one obtains a very complex envelope signal at the mix output. The signal contains 8 segments controlled by Attack 1, Decay 1, Attack 2, Decay 2, Attack 3, Decay 3, Attack 4 and Decay 4. The transition between the stages (i.e. when the following AD generator is triggered) is controlled by threshold knob. The positive or negative contribution of each unit to the mix signal is adjusted with the Mixing Polarizer control. If the trigger input of unit 1 is controlled by the comparator output of unit 4 one obtains a 8 stage LFO.

The single AD outputs can be used to control VCAs or VCFs that open one after another corresponding to the AD signals (a little bit similar to the Shepard generator A-191).

The default-connection between the four units (CPn = Trig.n+1) can be interrupted by patching cables into the trigger inputs. Consequently the four units can be used as separate AD generators or LFOs. In any case the mix signal is available (e.g. mix of four AD generators or LFOs with adjustable level and sign).

In the LFO mode the comparator output serves as LFO rectangle output with adjustable pulse width (= threshold control).

Each unit is equipped with a separate LED display for envelop and comparator output. The shortest attack/decay time is about 5 ms, the longest attack/decay times are about 3 seconds (attack) / 10 seconds (decay). By changing the value of a capacitor the shortest time can be modified (details can be found here: A100_Capacitors.htm).

The sketch at the bottom of the page shows the module principle with 4 daisy-chained AD units (as predetermined by the normalled sockets), that are mixed with the integrated polarizing mixer.

Notes: Module A-143-3 is a low-cost four-fold modulation oscillator, often called LFO (low frequency oscillator). Like the other modules of the A-143 series (A-143-1 and A-143-2) not a very "exciting" module, just a bread-and-butter device and a simple demon for work. The module contains four simple LFOs. Each LFO is equipped with three waveform outputs: triangle, rectangle and rising sawtooth. The frequency of the sawtooth output is twice the frequency of the other outputs. A three-way switch is used to select one of three frequency ranges mid-low-high, spanning from about two cycles per minute at the lowest, to moderate audio frequency at the highest (about 5 kHz).

If other waveforms or additional LFO features are required (e.g. reset input, adjustable waveform, voltage controlled frequency) the LFO modules A-145, A-146 and A-147 are available.

Notes: Module A-143-4 is a fourfold voltage controlled low frequency oscillator (LFO). As the frequency range includes moderate audio frequencies it can be used as a four-fold VCO too.

- Four independent VCLFOs/VCOs with triangle core
- Frequency range switches: low (bottom position) = LFO mode, high (top position) = VCO mode
- Two frequency control CV inputs for each unit
- CV1 without attenuator (~ 1V/oct)
- CV2 with attenuator
- Manual frequency control
- Internal jumpers for the frequency range of the manual frequency controls:
- Jumper not installed: ~ +/- 1 octave range (mainly for VCO applications)
- Jumper installed: ~ +/- 5 octaves range (mainly for VCLFO applications)
- Sync inputs: Combined Reset/Direction inputs for unit #1 - #3 / Separate Reset and Direction inputs for unit #4 (normalled sockets, i.e. Reset is connected to Direction if the Direction socket is unused) / Up/both/down direction switch for unit #4, for technical details concerning the Reset and Direction function please refer to the sketch below
- Triangle and rectangle outputs for each unit
- Typ. output voltage range -5V ... +5V for both outputs (i.e. about 10 Vpp, symmetrical with reference to 0 V)
- Red/yellow LED displays for the triangle outputs (red = negative output voltage, yellow = positive output voltage)
- Common control section with two CV inputs and manual control (these inputs and controls affect the frequency of all four units)
- Sum outputs for triangle and rectangle with red/yellow LED displays
- Optional ultra-low frequency mode: for this a negative voltage can be applied via a jumper internally to the CV2 input of each unit and the common section (i.e. a negative voltage is normalled to the socket CV2 in question). Then the CV2 - - Attenuator control works as a negative frequency control (i.e. turning up this control lowers the frequency). Herewith LFO periods up to about one hour (or even more) are possible.
- Optional CV bus access via jumper (i.e. the module can pick up the CV from the A-100 bus, e.g. generated by a Midi/CV or USB/CV interface A-190-x or a bus access module A-185-1/2), if the jumper is installed the bus CV affects all four units as the bus CV is added to the CV generated by the common control section
- Typ. frequency range: < 0.001 Hz (~ one hour, LFO mode with ultra-low option) ... 15 kHz (VCO mode with installed frequency range jumpers for the manual frequency controls)
- Heat-up time: ~ 15 minutes (required to heat-up the main circuit by the affixed oven)

The module was planned mainly as a quad VCLFO. But we added a range switch (nothing but a switch for two different capacitors) so that even audio frequencies are possible and the module can be used as VCO with some restrictions too. Because of the closeness of the main circuitry (i.e. four VCO cores within less ~ 1 square millimetre) the oscillators may lock if the frequencies are very close to each other and the VCO frequencies interact marginally. If a high quality quad VCO is required the A-111-4 is recommended as this module has four separate VCO circuits available.

The reset circuitry is optimized for the LFO mode. As it takes some time to discharge the oscillator capacitor the discharge time had to be chosen so that the capacitor is fully discharged in LFO mode. In the high range (where a much smaller capacitor is used) this will cause a zero state duration in the 0.3 ms range if the oscillator is synced (during this time the capacitor is shortened for discharge).
The control scale of the inputs "CV1" is about 1V/octave. To improve the behaviour in the VCO mode a tempco circuit is used to keep the temperature of the exponential converter at a fixed temperature (similar to the tempco option of the DIY SYNTH). That way the frequency of the VCOs (and even the VCLFOs) is nearly independent from the environment temperature. But the accuracy (1V/octave scale and temperature compensation) is not as precise as for the dedicated VCOs A-110 and A-111-1.

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-146 (LFO 2) is a Low Frequency Oscillator, which produces periodic control voltages over a wide range of frequencies.

The LFO can be used as a modulation source for a series of modules (for instance pulse width and/or frequency modulation of a VCO, modulation of a VCF cut-off frequency, amplitude modulation with a VCA).

Three outputs are available, with different waveforms: sawtooth / triangle; square wave, and positive-voltage square wave.

The waveform is continuously adjustable from rising sawtooth, through triangle to falling sawtooth. The same control affects the pulse width of the square wave.

A three-way switch can select one of three frequency ranges, spanning from one cycle every few minutes, at the lowest, up to audio frequency at the highest.

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.

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.

Notes: Module A-132-3 is composed of two identical voltage controlled amplifiers (VCA). Each VCA has a manual gain control 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 VCA's can be used to process both audio and control voltages. The input has no attenuator available but is capable to process up to 16Vss signals (i.e. -8V...+8V) without distortion.

Notes: Module A-120 is a voltage controlled low-pass filter, which filters out the higher parts of the sound spectrum, and lets lower frequencies pass through. The Cut-Off Frequency determines the point at which filtering takes effect. You can control this manually, or by voltage control (filter modulation, for instance by an LFO). Three CV inputs are available, and the sum of the voltages from these affects the filter cut-off.

The module is based on a so-called "transistor ladder" design, with a cut-off slope of -24 dB/octave, as in various Moog synthesizers. That's what gives it its classic, legendary Moog sound.

Resonance (or Emphasis) is adjustable all the way up to self-oscillation - in which case the filter behaves like a sine wave oscillator.

Notes: Module A-131 provides voltage-controlled amplification. For audio signals, you would normally use the exponential VCA (A-131), and for control voltages, the linear VCA (A-130). It doesn't always have to be that way, though.

The amount of amplification the VCA's provide is determined by the voltage at the CV input, and the position of the gain control, which sets the overall gain in the system.

The VCA has two audio inputs, each with an attenuator. They are amplified by an amount determined by the combination of the gain and the two CV controls.

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-149-1 is the first module of the A-149-x range. In this group we present by popular request several functions of Don Buchla's "Source of Uncertainty 265/266" (SOU) modules that cannot be realized with existing A-100 modules. Many functions of Buchla's 265 and 266 SOU can be realized with existing A-100 modules. For details please refer to A-100 patch examples.

Module A-149-1 has available four different analogue random control voltages that are generated in different ways.

The "Quantized Random Voltages" section has available 2 CV outputs: "N+1 states" and "2N states". N is an integer number in the range 1...6 that can be adjusted with the manual control (Man N) and an external control voltage CVN with attenuator. Whenever the rising edge of the input clock signal (Clk In) appears a new random voltage is generated at the N+1 resp. 2N output. The N+1 output is capable to generate N+1 different voltage levels (or states), the 2N output up to 2N different states. If for example N is set to 4 the N+1 output generates up to 5, the 2N output 16 different states. The voltage steps of the 2N output are adjusted to 1/12 V in the factory. Consequently, exact semitones can be obtained in combination with a VCO. The voltage steps of the n+1 output are adjusted to 1.0 V in the factory corresponding to octave intervals in combination with a VCO. For each output a trimming potentiometer is available on the pc board that enables the user to select other voltage steps for the output in question.

Even the "Stored Random Voltages" section has 2 stepped CV outputs available: one with even voltage distribution of the max. 256 output states and second one with adjustable voltage distribution probability. The distribution probability is adjusted by a manual control (Man D) and an external control voltage CVD with attenuator. With the control set fully counter-clockwise most of the random voltages will be low magnitude but even medium and high magnitude voltages may appear but with smaller probability. As the control is turned to the right (or a positive control voltage appears at the CVD input) the distribution moves through medium to high magnitude voltage probability. The symbol at the lower jack socket shows this coherence graphically. The voltage range is 0...+5V for both outputs of the "Stored Random Voltages" section. For each output a trimming potentiometer is available on the pc board that enables the user to select another voltage range for the output in question.

The A-149-1 can be extended by 8 random digital voltages with the A-149-2 Digital Random Voltages module.

Dimensions
12 HP
60 mm deep

Current draw
40 mA +12V
10 mA -12V

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-154 is a supplement to the A-155 Analog/Trigger Sequencer module. It offers a lot of new features that are not available in the basic control unit of the A-155. The A-154 is used to replace the control unit of one or two A-155, i.e. the section marked "Control" with Start / Stop / Step / Reset buttons and inputs in the upper left corner of the A-155 front panel. If the A-154 is used to control the A-155 the control section of the A-155 is put out of action.

These are the features of the A-154:

Several running modes: forward, backward, pendulum, random, CV controlled step addressing. All modes are available as loop or one-shot.

LED display of the 5 different current modes and one LED for loop/one-shot display

Manual and voltage controlled selection (with attenuator) of the running mode. If no external control voltage is applied one of the 10 modes (5 modes x 2 loop/one-shot) is simply selected with a rotary knob. The CV input with attenuator is used to modulate the running mode with an external control voltage (digital high/low CV to switch between two modes or continuous analogue CV to sweep through different modes). With the combination of manual control and CV with attenuator it is possible e.g. to use only two neighbouring modes (e.g. forward/backward) or sweep through all possible running modes

Manual and voltage controlled selection (with attenuator) of first and last step of the sequence. The range is step 1...8 in 8 step mode resp. 1...16 in 16 step mode

If the running mode "CV Controlled Step Address" is selected the First Step section is used to determine the active sequencer step. Consequently manual and voltage controlled selection (with attenuator) of the active step is possible: the active step can be set by hand with the first step manual control and then modulated by an external control voltage (e.g. LFO, Random, S&H, Theremin, Light CV source, Joy Stick) at the first step CV input (with attenuator).

An internal voltage controlled clock generator with manual and CV control (with attenuator) is available. The output of the clock generator is displayed with a LED and is used as sequencer clock provided that no external clock signal is connected to the Clock In socket (normalled socket). If the CV input of the Clock section is connected to one of the analogue outputs of the sequencer the time for each step can be set separately. Even jumps (or skipping) will be possible as we will introduce the feature that a very short clock pulse will be generated if the control voltage exceeds a certain value. For example the gate row of the A-155 can be used to obtain skipping of steps: the gate output simply has to be connected to the CV input of the A-154 clock generator. If the corresponding switch of the A-155 is set correspondingly in the gate row the step will be skipped.

Manual and voltage controlled (with attenuator) pulse width (PW) of the clock signal. This features can be used to obtain a different gate length for each step: e.g. one of the CV outputs of the A-155 can be used to control the PW. With a PW control voltage coming from a LFO/random/S&H the gate length will change automatically. CV coming from Theremin A-178, ribbon controller A-198, light controlled CV A-179, joy stick A-174 are other ways to control the gate length.

8/16 step mode: A toggle switch us used to select 8 or 16 steps. The "16 step" mode requires two A-155 and one or more voltage controlled switches (e.g. A-150-1 or A-150-8). The voltage controlled switches are controlled by the "A3" output of the A-154. This output remains "low" as long as the active step is in the range 1...8 and turns to "high" in the range 9...16. The voltage controlled switches are used to switch between the CV/trigger/gates outputs of the first A-155 (step 1...8) and the second A-155 (step 9...16). In the A-154 user's manual the corresponding patch is shown.

If two A-155 are used they can work in parallel (8 steps) or serial (16 steps). The 8/16 steps switch determines if the 8 step mode (one A-155 or two A-155 in parallel) or the 16 step mode (two A-155 serial) is chosen. Both modes work with CV controlled step addressing too (see below). In 8 step mode only the steps 1...8 are addressed, in 16 step mode the steps 1...16. For serial operation an additional VC switch (A-150) is required - as mentioned above.

Notes: Module A-154 is a supplement to the A-155 Analog/Trigger Sequencer module. It offers a lot of new features that are not available in the basic control unit of the A-155. The A-154 is used to replace the control unit of one or two A-155, i.e. the section marked "Control" with Start / Stop / Step / Reset buttons and inputs in the upper left corner of the A-155 front panel. If the A-154 is used to control the A-155 the control section of the A-155 is put out of action.

These are the features of the A-154:

Several running modes: forward, backward, pendulum, random, CV controlled step adressing. All modes are available as loop or one-shot.

LED display of the 5 different current modes and one LED for loop/one-shot display

Manual and voltage controlled selection (with attenuator) of the running mode. If no external control voltage is applied one of the 10 modes (5 modes x 2 loop/one-shot) is simply selected with a rotary knob. The CV input with attenuator is used to modulate the running mode with an external control voltage (digital high/low CV to switch between two modes or continuous analog CV to sweep through different modes). With the combination of manual control and CV with attenuator it is possible e.g. to use only two neighbouring modes (e.g. forward/backward) or sweep through all possible running modes

Manual and voltage controlled selection (with attenuator) of first and last step of the sequence. The range is step 1...8 in 8 step mode resp. 1...16 in 16 step mode

If the running mode "CV Controlled Step Address" is selected the First Step section is used to determine the active sequencer step. Consequently manual and voltage controlled selection (with attenuator) of the active step is possible: the active step can be set by hand with the first step manual control and then modulated by an external control voltage (e.g. LFO, Random, S&H, Theremin, Light CV source, Joy Stick) at the first step CV input (with attenuator).

An internal voltage controlled clock generator with manual and CV control (with attenuator) is available. The output of the clock generator is displayed with a LED and is used as sequencer clock provided that no external clock signal is connected to the Clock In socket (normalled socket). If the CV input of the Clock section is connected to one of the analog outputs of the sequencer the time for each step can be set separately. Even jumps (or skipping) will be possible as we will introduce the feature that a very short clock pulse will be generated if the control voltage exceeds a certain value. For example the gate row of the A-155 can be used to obtain skipping of steps: the gate output simply has to be conneted to the CV input of the A-154 clock generator. If the corresponding switch of the A-155 is set correspondingly in the gate row the step will be skipped.

Manual and voltage controlled (with attenuator) pulse width (PW) of the clock signal. This features can be used to obtain a different gate length for each step: e.g. one of the CV outputs of the A-155 can be used to control the PW. With a PW control voltage coming from a LFO/random/S&H the gate length will change automatically. CV coming from Theremin A-178, ribbon controller A-198, light controlled CV A-179, joy stick A-174 are other ways to control the gate length.

8/16 step mode: A toggle switch us used to select 8 or 16 steps. The "16 step" mode requires two A-155 and one or more voltage controlled switches (e.g. A-150-1 or A-150-8). The voltage controlled switches are controlled by the "A3" output of the A-154. This output remains "low" as long as the active step is in the range 1...8 and turns to "high" in the range 9...16. The voltage controlled switches are used to switch between the CV/trigger/gates outputs of the first A-155 (step 1...8) and the second A-155 (step 9...16). In the A-154 user's manual the corresponding patch is shown.

If two A-155 are used they can work in parallel (8 steps) or serial (16 steps). The 8/16 steps switch determines if the 8 step mode (one A-155 or two A-155 in parallel) or the 16 step mode (two A-155 serial) is chosen. Both modes work with CV controlled step addressing too (see below). In 8 step mode only the steps 1...8 are addressed, in 16 step mode the steps 1...16. For serial operation an additional VC switch (A-150) is required - as mentioned above.

The functions of the Start/Stop/Step/Reset buttons and inputs are the same as for the "old" control unit of the A-155:

A high level at the Start input or operating the Start button starts the sequence from the momentarily addressed step. Not working in "CV controlled step address" mode.

A high level at the Stop input or operating the Stop button stops the sequence (the last active step remains addressed). Not working in "CV controlled step address" mode.

Notes: The Doepfer A-155 has two CV rows, each with selectable voltage range, glide and sample & hold options. Three trigger rows and a one gate row. Logic inputs for clock, reset, start and stop. It's even possible to insert external signals per step instead, overriding the CV generated by the 2nd row's potentiometer. The A-155's functions can be expanded by the A-154 Sequencer Controller, as it's an entire control unit with step number limitation, voltage controllable clock generator, variable gate length and a number of playback modes.

Features of the analogue rows (knobs):

- 8 potentiometers (knobs)
- Lower row: Scale (knob), voltage output range 0 ... ~ +6,5V
- Upper row: 1V/2V/4V (octave range switch for exact VCO control), voltage output ranges 0 ...1.0V / 0 ...2.0V / 0 ...4.0V
- Glide time (knob), same as portamento or slew limiter
- Glide Control (control input for switching glide on/off)
- S&H Control (control input for internal S&H, works like A-148)
- Pre Glide/S&H-Out (analogue output before S&H and glide unit, especially required when external audio signals are used as inputs of the lower row)
- Post Glide/S&H-Out (analogue output after S&H and glide unit)
- Lower row: external inputs for the 8 steps (switched jack sockets), control signals or audio signals may be used as inputs (allowed voltage range -5V...+12V), the knobs of the lower row are working in this case as attenuators

Features of the trigger rows (switches):

- 4 Trigger/Gate tracks with 2 rows of switches
- Toggle switches of 1-0-1 type (with middle position), which can be used to send a trigger/gate to the track above or below or to send no trigger/gate (middle position)
- 3 trigger rows (i.e. short pulse for each step set, pulse width corresponds to the pulse width of the clock/step input signal)
- 1 gate row (i.e. a high signal is applied during the length of the step set)

Control inputs and buttons:

- Step (defines the tempo of the sequence, same as clock or trigger input)
- Reset (resets all rows to step 1)
- Start (starts the sequence at the momentary position)
- Stop (stops the sequence at the momentary position)

Step and Reset are compatible to the MIDI interface A-190, i.e. in combination with the A-190 the A-155 may be synchronized via MIDI. The quantizing module A-156 can be used to quantize the infinite analogue voltages coming from A-155 into discrete semitone steps (multiples of 1/12V). Without MIDI interface e.g. a LFO rectangle output can be used to define the tempo of the sequence.

The sequencer controller A-154 adds a lot of new functions to the A-155 (e.g. voltage controlled addressing, forward/backward/pendulum/random mode, voltage control of first and last step, voltage controlled clock and gate length, step skipping, combination of several A-155 in parallel/serial mode and many more).

Notes: Module A-156 is a Dual Control Voltage Quantizer. A quantizer converts a continuous control voltage in the range 0...+10V into a stepped output voltage in the same voltage range (i.e. only certain voltages occur). Normally 1/12 V steps are used to obtain semitone steps. Quantizer 2 of the A-156 allows has more sophisticated quantizing modes like major scale (i.e. only voltages corresponding to the major scale), minor scale, major chord, minor chord, fundamental + fifth and addition of seventh or sixth when chords are selected. Only those voltages appear at the CV output which comply with the selection rule (e.g. minor chord with seventh). The mode setting of quantizer 2 is done with 3 switches (1-0-1 type with middle position). From the factory quantizer 1 is working in the semitone mode. But there is a jumper on the pc board that can be changed so that even quantizer 1 uses the same scale as quantizer 2.

For each quantizer the following in/outputs are available:

- Control voltage input (CV In): The input for the continuous voltage to be quantized
- Control voltage output (CV Out): The output of the quantized voltage
- Trigger input (Trig.In): If this jack is left open the quantizer is working permanently. If a rectangle voltage is applied quantisation happens only at the rising edge of the signal (e.g. from an LFO or MIDI-to-Sync interface). Thus the quantizing can be synchronized with other events
- Trigger output (Trig.Out): Whenever a quantisation happens (i.e. a new voltage is generated at the CV Out) a positive pulse occurs at this output. It may be used to trigger an envelope generator (ADSR) or for triggering other modules (sequential switch A-151, trigger divider/sequencer A-160/161, trigger delay A-162, ...). If none of these functions are used the jack is left open

On top of that the A-156 is provided with a common transpose CV input having an additive effect on both quantizers. This input is quantized in semitone steps. A typical application is the transposition of a sequence generated by the A-155 by a second control voltage (e.g. coming from the MIDI-CV interface A-190).

Typical applications:

- Quantizing the CV sequence generated by an A-155 (semitone, only major scale, only minor scale and so on)
- Quantizing the voltage coming from the Trautonium Manual / Ribbon Controller A-198, Theremin A-178 or Light-to-CV module A-179 to get accurate semitones or major/minor scale tones
- Arpeggio-like effects with LFO, random, noise, envelope generators as CV sources (for negative or symmetrical voltages an offset must be added, e.g. with the offset/attenuator module A-129-3, to obtain positive voltages for the A-156 input)

Notes: A-157 is a trigger sequencer subsystem that generates eight trigger signals controlled by a 8x16 LED/button matrix (some customers call it "Miniature Schaltwerk" as it is based on the same matrix as the no longer available Schaltwerk).
The subsystem contains three modules:

A-157-1: 8 x 16 LED/button matrix and function addressing buttons/LEDs
A-157-2: Trigger Output module
A-157-3: Control Inputs module

The LED/button matrix module A-157-1 is the core of the subsystem. It is used to set or reset the trigger event on each of the 16 steps of each of the 8 rows. In addition the buttons and LEDs of the matrix are used for other functions too (like setting the first and last step of each row or addressing the preset memory).

The Trigger Output module A-157-2 outputs the 8 trigger signals and has an LED display for each trigger available.

The Control Inputs module A-157-3 has manual controls and trigger inputs available for the basic control functions start, stop, reset and clock. In addition four functions inputs are available which will be used in future firmware versions to assign these inputs to special functions (e.g. shifting a row left or right by means of an external gate/trigger signal or a second set of start, stop, reset and clock for individual rows).

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-160-5 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-162 contains two identical circuits that generate a trigger signal with adjustable delay and length from an incoming rectangle signal (e.g. gate, trigger, rectangle output of an LFO or VCO). The rising edge of the incoming signal is used to trigger the new trigger signal. This module makes it possible to delay the onset of a trigger pulse, and also change its length.

On each of the two units, two controls can alter the onset time and duration of triggers, from about 2 ms up to more than 10 seconds. A control LED shows the generated signal.

Notes: Module A-163 is a voltage controlled audio frequency divider. The frequency of the input signal (preferably the rectangle output of a VCO) is divided by an integer factor N (N = 1, 2, 3, 4 ... up to 32). N can be adjusted manually and modulated with an external control voltage (e.g. from LFO, ADSR, Random, MIDI-to-CV, Theremin, Light-to-CV, analogue sequencer) with attenuator. The control input has polarizing function, i.e. the manually adjusted dividing factor can be modulated upwards or downwards. The basic idea of a polarizer is described in the modules A-133 Voltage Controlled Polarizer and A-138c Polarizing Mixer.

The output waveform is rectangle with 50% duty cycle. Unlike the A-115 with fixed dividing factors (2, 4, 8, 16) the dividing factor of the A-163 is voltage controlled and can be any integer value between 1 and about 20 (but only one output). In contrast to A-113 the dividing factor of the A-163 is voltage controlled and the output waveform is rectangle (the A-113 has 4 sawtooth outputs with 4 adjustable but not voltage controlled dividers).