Doepfer A-143-4 Quad VC-LFO/VCO

The A-143-4 contains four voltage controlled LFOs / VCOs with triangle and rectangle outputs in one single module.

Each sub unit has a potentiometer and two CV inputs for controlling the frequency and ouptuts triangle and square wave forms.

Beyond this there´s a common reset/direction input for units 1-3 and separate reset and direction inuts at unit four. Direction determines in which direction the LFO will oscillate after having received a reset, either upwards or downwards. When no cable is plugged int the direction jack, the reset is normalized to it.

The frequency range can  be switched between low and high, thus it can produce frequencies up to 15kHz. Each unit can be used as a VCO as well, wlthough the tracing is not exactly 1V/octave. The LFOs/VCOs are temperature compensated and after a heating time of 10 miutes they run stable, independent of the outside tepmerature.

In addition there´s a common section for all four LFOs: it contains CV inputs and potentiometers for simultaneous frequency control of the LFOs and outputs carrying mixtures of the triangle and the rectangle outputs.

Bicolor LEDs diyplay the phase of the traingle (orange = positive / red = negative). A number of jumpers on the back side set different frequency ranges, they de-/activate frequency control via the internal CV buss or set the control range of the frequency potantiometers (either 1 or 5 octaves).