The thru-zero frequency modulation of Rubicon is ideal for experimenting with FM synthesis. Rubicon is an analog VCO design masterpiece, originially created by Dave Dixon with Intellijel. It is a unique Eurorack module, now offered as an add-on module for Modular.
The Rubicon is an analog triangle core VCO that is capable of thru-zero frequency modulation. It is a feature packed VCO with multiple simultaneous waveform outputs, including waves that are multiples or divisions of the base frequency.
High precision emulated Triangle core
Switchable linear and (for the first time in any module) exponential TZFM (through-zero FM)
Linear index VCA for dynamic control of TZFM depth
Symmetry control (full clockwise is normal, full counter-clockwise gives reversed waveforms, centered the VCO is at 0 Hz) with CV
12 primary waveform types: sine, sigmoid, double sigmoid, triangle, saw, double saw, zigzag, square, pulse (center modulated), pulse (edge modulated), double pulse
Suboctave circuit with -1 and -2 octaves. The suboctave output is affected by fm just like the main signals
Soft sync (also known as reversing sync) with attenuator
Hard sync with selectable reset direction (determines if the triangle starts moving up or down after a reset, very useful in LFO mode)
Pulse-width modulation and exponential FM with dedicated attenuators
Requires Softube Modular