Cosmotronic - Vortex
The Vortex is a 100% analog dual VCO with waveshapers, through-zero capabilities and pre-patched FM possibilities - a true Complex VCO.
There are some other established complex VCOs, but most of them have the tendency to be complex not only technically, but also their user interface. The Vortex is probably the most clearly laid-out – (in terms of the controls) complex VCO.
Two VCO's, each with a unique waveshaper and folder and a 2-pole low pass filter - which works great to soften the harsher tones from complex intermodulation. An FM index bus lets you patch complex cross modulations using exponential and thru zero linear FM. The left VCO can be phase modulated, while the right VCO can be amplitude modulated, and everything under CV control.
Both VCOs can be used independent from each other, there is no distinction between a carrier and modulator. The left VCO lets you morph between a triangle and saw waveform, which is also available at a separate output. After that the signal goes into a sinusoidal wavefolder, based on a modified version of a design by Barrie Gilbert from 1977. This special circuit design allows Thru Zero Phase Modulation. For this also external modulation sources can be patched in, and the depth can be modulated. The final stage of the signal path for the left VCO is a 2-pole Low Pass Filter. All parameters can be controlled by CV and feature handy attenuators at the inputs.
The right VCO features a continuous waveform shaper, that morphs from sine to triangle to saw. From here the signal enters the Thru Zero Amplitude Modulation (Ringmod) section. The depth can be CV controlled, and an external source can be patched as well. The result is also available on a separate output, pre wavefolder/filter. The wavefolding part of the right VCO is based around a novel wavefolding topology, with a unique and more aggressive sound compared to the sinusoidal folder of VCO 1. The last part of the signal path is also a 2 pole Low Pass Filter.
All in all, you get a 100% analog complex oscillator, featuring two independent VCO's. Both voices have a unique signal path and flavor. Features include the Thru Zero trinity: Frequency, Phase and Amplitude modulation. The FM bus modulates the index of each individual voice, including linear and exponential inputs for external sources and you also get inputs for Sync in, with both soft and hard sync.