Doepfer

Notes: ***B-STOCK: Slight dent om the edge, otherwise in perfect condition***


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-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-147-4V 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 resolution. 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.

Power consumption: 80mA at +12 V and 70mA at -12 V
Depth: 45mm
HP : 8