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Doepfer A-147-2v Voltage Controlled Delayed LFO (Vintage Series)


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-color 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.

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).

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 unicolor LED (probably orange) and available at the "Delay Out" socket.


Output level Triangle, Sine and Rectangle: about -4...+4V (symmetrical)
Output level sawtooth: about 0...+8V (positive only)
Frequency range without external CV: about 0,005Hz (about 3 minutes) ... 200Hz
Frequency range in ultra low mode or external CV: about 1 hour period ... about 1kHz
Trigger level for LFO Reset/Delay Reset: about min. 6 Vpp (AC coupled, i.e. the voltage difference is essential)
VCA CV/amplification: 0....+5V for amplification 0...+1 (in VCA mode), 0...+5V for amplification -0,5...+0,5 (in polarizer mode)
Delay range: about 5ms ... about 2 minutes

Technical Specs

  • 8 hp
  • 60 mA +12V
  • 60 mA -12V
  • 0 mA 5V
  • 60 mm deep

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