A-143-4 Quad VC LFO VCO - 22HP

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Item: N13-4553

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A-143-4 Quad VC LFO VCO - 22HP


The Doepfer ‘A-143-4 Quad VCLFO/VCO’ is fourfold voltage controlled Low Frequency Oscillator (LFO) Eurorack module which can also function as a fourfold VCO as well. The module features four independent VCLFOs/VCOs with triangle cores. Although planned mainly as a quad VCLFO, the A-143-4 is equipped with a range select switch so that even audio frequencies are possible and the module can be used as a VCO (with some restrictions). Because of the closeness of the main circuitry (i.e. four VCO cores within less than 1 square millimeter) the oscillators may lock if the frequencies are very close to each other. 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 "CV 1" are about 1V/Octave. To improve the behavior 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) are nearly independent from the environment temperature. However, the accuracy (1V/Octave scale and temperature compensation) is not as precise as the dedicated VCOs A-110 and A-111-1. 


  • Quad VCLFO/VCO Module
  • Independent operation of all 4 VCLFOs/VCOs
  • CV 1 and CV 2 Inputs for all 4 VCLFOs/VCOs
  • CV 1 and CV 2 Inputs for Common (Global) Control
  • CV 2 Input Control for all 4 VCLFOs/VCOs
  • CV 2 Input Control for Common (Global) Control
  • Frequency Control for all 4 VCLFOs/VCOs
  • Common (Global) Frequency Control
  • A, B, C, D, VCLFOs/VCOs all have Triangle And Rectangle Waveform Outputs with LED Indication
  • Common (Global) Output Sums of Triangle and Rectangle Outputs with LED Indication
  • D - VCLFO/VCO has both RESET and DIRECTION CV Inputs
  • D - VCLFO/VCO has DIRECTION select switch (UP/DOWN)
  • All 4 VCLFOs/VCOs have a Select Switch for VCO/VCLFO operation

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  • Eurorack Module
  • 22 HP Width
  • 60mm Depth
  • Current Draw: 100mA @ +12V

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