Doepfer A-110-6 Trapezoid Thru Zero VCO

Exotic VCO – The A-110-6 utilizes a quadrature trapezoid core to generate sound. Waveshapers are used to derive other signals. In total, the module emits five waveforms plus variations with a phase shift of 90 degrees. The oscillator’s frequency is determined by an exponential and a linear control stage. An LFO mode allows users to employ the A-110-6 as a modulator. Thanks to its thru zero circuits, the module delivers beefy FM sounds. In combination with the phase-shifted outputs, it is possible to create lots of extraordinary timbres.

Contrary to traditional VCOs, the A-110-6 isn’t based on a sawtooth or triangle core, but a quadrature trapezoid design. The module offers ten outputs, which emit the following signals:

• TraSin – Trapezoid waveform
• TraCos – Trapezoid waveform with a phase shift of 90 degrees
• Sine – Sine waveform
• Cosine – Sine waveform with a phase shift of 90 degrees
• TriSin – Triangle waveform
• TriCos – Triangle waveform with a phase shift of 90 degrees
• RecSin – Square waveform
• RecCos – Square waveform with a phase shift of 90 degrees
• SawSin – Sawtooth waveform
• SawCos – Sawtooth waveform with a phase shift of 90 degrees

The A-110-6 comes equipped with an exponential and a linear control stage. The first-mentioned section features a frequency potentiometer (XTune), a modulation input plus attenuator (XFM) and a 1V/octave connector. The linear stage is composed of yet another frequency potentiometer (LFrq) and modulation input plus attenuator (LFM). The oscillator’s pitch is determined jointly by both sections. While the LFrq potentiometer is set fully clockwise, the A-110-6 behaves like an ordinary VCO. When the control element is moved counterclockwise, the module’s frequency changes with linear characteristic. In middle position, the waves (nearly) stop. With the LFrq potentiometer turned fully to the left, the oscillator behaves like an ordinary VCO again. - But with inverted wave direction.

A switch allows users to change the module’s frequency range. Thanks to this feature, the A-110-6 can not only be utilized as an audio generator, but a LFO as well.