DOEPFER / A-110-4SE Thru Zero Quad VCO

Variations

A module from the German synthesizer manufacturer Doepfer. It's an oscillator capable of generating extremely pure sine/cosine waves with minimal harmonics and distortion.

The A-110-4 Thru Zero Quadrature VCO is an oscillator module. ""Quadrature"" refers to this connection that outputs both sine and cosine waves simultaneously. ""Thru Zero"" implies the generation of negative frequencies. However, this is misleading; negative frequencies do not actually exist. ""Negative"" simply means that when the linear CV reaches 0V, the sine/cosine waves stop, and when the linear CV moves in the opposite direction, the sine/cosine waves become out of phase.

This module has two sections: linear and exponential. The exponential section consists of an XTune control, a 1V/Oct input, and an XFM input and XFM attenuator. The exponential CV is the sum of these three voltages. The linear section consists of an LFrq control, an LFM input, and an LFM attenuator. The linear CV is the sum of these two voltages. The dual-color LED displays the polarity of the linear control voltage (red = positive / yellow = negative).

A key advantage of the A-110-4 compared to other through-zero VCOs is its sine/cosine core. Sine/cosine waves are not generated from other waveforms (e.g., sawtooth or triangle waves). The A-110-4 can generate extremely pure sine/cosine waves with minimal harmonics and distortion.

■Width: 8HP
■Depth: 60mm
■Current Consumption
+12V: 90mA
-12V: 30mA