Doepfer A-110-2 Eurorack Basic Voltage Controlled Oscillator Module

Doepfer A-110-2 - Basic VCO

The Doepfer A-110-2 is a low-cost voltage-controlled oscillator. It’s a slight reduced version of the standard VCO A-110-1. Compared to the A-110-1 the A-110-2 has no sine output and the (expensive) octave rotary switch is replaced by a three-position toggle switch. In return the A-110-2 is equipped with an additional linear frequency modulation input and a soft sync input. A jumper is used to select the range of the tune control between about ½ octave and about four octaves. The width of the module is only 8hp to the 10hp of the A-110-1. All the other features are essentially the same.

The core of the A-110-2 is like the A-110-1. A sawtooth oscillator (in contrast to the A-111-1, which is based on a triangle oscillator). The other waveforms are derived from the sawtooth by waveform converters.

The sawtooth output of the A-110-2 has a falling (or negative) slope. The front panel erroneously shows a rising (or positive) slope. This has no influence to the sound but becomes important when the module is used an as LFO or is mixed with the sawtooth output of another VCO.

The control voltage applied to the socket 1V / Octave is added to the control voltage coming from the bus (interruptible by removing the jumper JP2). Connecting a cable to the socket 1V / Octave does not interrupt the bus CV connection.

To obtain also a sine signal the triangle to sine converter module, A-184-2, is recommended. It includes also a voltage-controlled crossfader to fade between two waveforms.

Jumper and Trimming Potentiometers

• JP2: CV connection to A-100 bus

• JP3: range of Tune control (installed = about 4 octaves, not installed = about ½ octave)

• JP4: AC/DC coupling of the linear Frequency Modulation input (installed = DC coupling, not installed = AC coupling)

• P5: 1v / Oct scale

• P6: frequency offset

• P7: high-end trim

• P8: adjustment +1 Oct. range switch

• P9: adjustment -1 Oct. range switch

• P10: temperature VCO heater

Specifications