Intellijel Rubicon User Manual

Intellijel RubiconManual Version1

The Rubicon is an analogue triangle core VCO that is capable of through 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.

Front Panel details

1- COARSE knob- Sets the frequency of the oscillator.
2 - LFO/VCO switch - Changes the base frequency range from very slow (LFO) to audio (VCO)
3 - FINE knob – Allows finer adjustment of the coarse frequency over a range of +/-6 semitones
4- SINE TYPE switch - SINE on the left, SIGMOID in the middle, SIGMOID at double the base

frequency on the right (sine is what you get when you push a triangle wave to a sine shaper, and
sigmoid is what you get when you push a sawtooth wave through a sine shaper -- it sounds a lot like a
saw, but a bit warmer and can be great for creating metallic sounds.

5- SYMMETRY knob - Determines the direction and magnitude of the waveform through the linear FM
circuit -- fully CW gives output at the positive base frequency, fully CCW gives output at the negative

Page|1


Intellijel RubiconManual Version1

base frequency, and in the centre the VCO stops oscillating (zero frequency). If fully CW, then a signal
into TZFM gives conventional Linear FM. Ditto for fully CCW, but the output frequencies are negative
(which simply means that all of the waveforms are backwards -- except the zigzag, strangely enough).
For normal VCO sounds set this at full CW.

NOTE: Symmetry affects 1V/Oct tracking! For the best tracking put SYMMETRY in full CW position.

6 - TZFM knob - Sets the Bias of the TZFM VCA. As the knob is turned CW more of the signal patched
into the TZFM input will modulate the VCO frequency. (Remember, the SYMMETRY setting determines
whether the FM is conventional linear, partially through-zero , or balanced through-zero)

7 - mini knob for TZFM attenuation - This attenuates the audio/cv signal coming into the INDEX input
below. This is the attenuated modulation input for a linear VCA which virtually turns the TZFM knob.
This is the "dynamic" modulation of through-zero FM. In other words, it modulates the modulation. It's
the "adverb" to TZFM's "adjective" so to speak. That's why it is shown as the control input to a VCA on
the panel. The INDEX input is like the CV input of a VCA, and the TZFM knob is like the Bias of that
VCA, where that VCA controls the degree of through-zero (or just linear) FM.

8 - TZFM EXP/LIN switch - Selects the type of FM modulation the TZFM input will be.
This switch determines whether the response of TZFM is linear or exponential. The exponential setting
is not really 1V/oct, and really just gives a more extreme response to the modulation signal

9 - SUB OCT switch - Selects if the SUB output is down one octave or two octaves from the VCO base
frequency.

A - Input jacks - CV and audio signals are patched into here.
B - Output jacks - As will all Intellijel modules the outputs have filled boxes around them.
C - EXP FM knob - Sets the attenuation of the signal patched into the EXP FM input, modulates the

conventional expo FM circuit (gives 1V/octave response when the attenuator knob is turned fully CW)
D- Pulse Type switch - Centered pulse on the left, edge aligned pulse in the centre, edge aligned

pulse at double the base frequency on the right (centre pulse is what you get when you send the triangle
wave to the pulse comparator, and edge pulse is what you get when you send the sawtooth wave to the
pulse comparator -- they are the same, but they have a different phase relationship to each other, so
they do different things when blended with the other waveforms)

E – PW knob - This knob offsets the pulse width of the Pulse waveform out.
F - mini knob - Attenuates the signal going into the PWM input.
G - RESET switch - Selects whether the HARD sync input will reset the VCO to a rising or falling

direction.

Page|2


Intellijel RubiconManual Version1

IO Section Details

INPUTS
1 - 1V/OCT - Controls the frequency of the VCO. 1 volt increments double the frequency of the VCO.
2 - INDEX - CV input of the VCA in the TZFM path. There is a mini attenuator on this input.
3 - TZFM - FM input that can be switched LINear or EXPonential with the switch above it. The amount of

this input is controlled by the VCA. The VCA is controlled by the TZFM knob and INDEX input.
4 - SYM - This modulates the symmetry setting, and is equivalent to turning the symmetry knob back

and forth. This is the "non-dynamic" modulation of through-zero FM. There is a mini attenuator on this
input.

5 - SOFT – Soft sync, the triangle wave reverses on the incoming sync pulse, and the attenuator sets
the probability that a pulse will cause reversing. Requires edge-y waveforms like square or sawtooth
(sawtooth is best). There is a mini attenuator on this input.

6 - HARD - hard sync input. Traditional VCO sync that resets the Rubicon when the input VCO or
Master crosses zero. Use the RESET switch above it to select if the waves will reset rising or falling.

7 - PWM - Pulse Width Modulation CV input for modulating the pulse with of the Pulse wave.
There is a mini attenuator on this input.

8 - EXP FM - input for traditional exponential FM. Does not go through zero. use for pitch bend and FM
sounds that do not have to track the 1v/oct input such as percussion. The EXP FM knob attenuates this
input. Gives 1V/octave response when the attenuator knob is turned fully CW

OUTPUTS
A - Sine wave - Waveform selected by the SINE TYPE switch. Wave types: Sine, Sigmoid, Double

Frequency Sigmoid.

B - Triangle wave.
C - Saw wave

Page|3
