Doepfer A-111-3 Micro Precision VCO

Doepfer A-111-3 Micro Precision VCO

The Micro Precision VCO is a space-saving and utterly precise analog VCO/LFO with a extremely big frequency range, immaculate tracking over at least ten octaves and nearly perfect waveforms.
Basically it is the same circuitry like the High-End VCO A-111-2 but with reduced functions and controls. Yet it is super suitable as a modulator for exact linear FM and much more.

The A-111-3 has two elements for setting the frequency: a switch selecting between LFO and VCO mode as well as a tune control with a jumper-selectable range:

- jumper position 1: 16Hz to 20 kHz
- jumper position 2: 16Hz to 70Hz
- without jumper: 16Hz to 22Hz

The XM potentiometer can be used as a fine tune control as long as nothing is patched to the XM socket.

The oscillator has a frequency range of at least fifteen osctaves (0.0001 - 40Hz in LFO mode; 0.5Hz to 20kHz in VCO mode) and offers perfect 1V/octave tracking over ten octaves minimum, typically in the range of 20Hz to 20 kHz. Frequencias below 25Hz are visualized with a two-color LED.
The 1V/octave input is accompanied by two FM inputs, one for linear and one for exponential frequency modulation. A jumper determines whether the module obtains pitch CV via the internal bus.

The VCO has a triangle core from which sawtooth, pulse and sine are derived. The wave forms are almost perfect and sans glitches.
The pulse width can be set with a control from 0 to 100% and of couse it can be modulated.
There is one input for oscillator synchronisation and its type, either hard or soft sync, is jumper-selected. Both types differ in sound with the hard sync being more aggressive and richer in harmonics.

• 40 mA +12V
• 40 mA -12V
• 0 mA 5V