Instruo cnoc User manual

cnōc
Function Generator
User Manual

2
Contents
3
Description / Features
4
Installation / Specifications
5
Overview
6
Signal I/O
7
Function Generator
9
Patch Examples
- West Coast Synth Voice
- East Coast Synth Voice
- CV Slew Limiter
- Quadrature Moulation

3
Description
The Instruō cnōc is a fully analogue voltage-controlled two stage
function generator. This style of function generator was pioneered by
the West-coast mindset of sound synthesis and goes far beyond the
functionality of a traditional envelope generator. With AR, ASR, and
Looping modes, as well as its unipolar positive and bipolar outputs,
cnōc finds its home in any patch.
Whether you need a general envelope generator, LFO, delayed gate
signal, or a slew limiter to add portamento to your pitch sequences,
cnōc fits the bill.
Features
• AR, ASR, and Looping envelope modes
• External control over Attack and Release stages
• Unipolar positive and bipolar outputs
• Assignable gate output
• Manual trigger button
• Slew limiting functionality
• Two response curve settings

4
Installation
• Confirm that the Eurorack synthesizer system is powered off.
• Locate 4 HP of space in your Eurorack synthesizer case.
• Connect the 10 pin side of the IDC power cable to the 2x5 pin
header on the back of the module, confirming that the red stripe on
the power cable is connected to -12V.
• Connect the 16 pin side of the IDC power cable to the 2x8 pin
header on your Eurorack power supply, confirming that the red
stripe on the power cable is connected to -12V.
• Mount the Instruō cnōc in your Eurorack synthesizer case.
• Power your Eurorack synthesizer system on.
Note:
This module has reverse polarity protection.
Inverted installation of the power cable will not damage the module.
Specifications
• Width: 4 HP
• Depth: 27mm
• +12V: 45mA
• -12V: 40mA

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cnōc | kn·Uk | noun (landscape) a natural elevation or raised
landscape; an accumulated heap or mound
Key
1. Signal Input
2. Bipolar Output
3. Unipolar Positive Output
4. EOC Output
5. Gate Output
6. Stage Gate Toggle
7. Response Curve Switch
8. Attack Fader
9. Attack CV Input
10. Release Fader
11 . Release CV Input
12. Mode Toggle
13. Trigger/Charge Direction Button
cnōc
A
IN
R
OUT
GATEEOC
±+
4
2 3
11
1
5
6
12
13
7
8
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10

6
Signal I/O
Signal: The Signal input is a bipolar input used for function generation.
• A trigger or gate signal present at the Signal input will ping an
envelope at the Bipolar and Unipolar Positive outputs.
• If the Mode toggle is set to ASR Mode, a control voltage signal
present at the Signal input will be slewed at the Bipolar and
Unipolar Positive outputs based on the settings of the Attack and
Release faders (See the Mode, Attack, and Release sections for
more information).
Bipolar: The Bipolar output is a bipolar control voltage output.
• Output range: 10Vpp.
Unipolar Positive: The Unipolar Positive output is a unipolar positive
control voltage output.
• Output range: 0V - 10V.
EOC: The EOC output will output a 1ms trigger signal at the end of
each cycle.
• Output voltage: 10V.
Gate: The Gate output will output a gate signal for the duration of either
the Attack stage or the Release stage, based on the position of the Gate
Mode toggle.
• Output voltage: 10V.
Stage Gate: The Stage Gate toggle determines whether the gate
signal present at the Gate output is in relation to the Attack stage or the
Release stage.

7
Function Generator
Response Curve: The Response Curve switch controls the contour of the
function.
• Setting the switch to its left position will set the function to a linear
response curve.
• Setting the switch to its right position will set the function to a
logarithmic/exponential response curve.
• This setting will have a logarithmic Attack stage and an
exponential Release stage.
Attack: The Attack fader defines the onset duration of the function. The
value set by this control is measured in the time domain.
• Moving the fader upward will increase the attack time.
• Moving the fader downward will decrease the attack time.
• The fader’s LED will illuminate with ascending voltage.
Attack CV: The Attack CV input is a bipolar control voltage input for the
Attack parameter.
• Control voltage is summed with the fader position.
Release: Once the Attack stage has completed, the Release fader
defines the time it takes for the function to to return to its starting voltage.
• Moving the fader upward will increase the release time.
• Moving the fader downward will decrease the release time.
• The fader’s LED will illuminate with descending voltage.
Release CV: The Release CV input is a bipolar control voltage input for
the Release parameter.
• Control voltage is summed with the fader position.

8
Mode: The Mode toggle sets the function mode.
• If the toggle is in the left position, the function is set to ASR (Attack/
Sustain/Release) Mode.
• If the toggle is in the centre position, the function is set to AR (Attack/
Release) Mode.
• If the toggle is in the right position, the function is set to
Looping Mode.
• Cycle times in Looping Mode range between ~1ms
(oscillation of ~1 kHz) and ~20s (oscillation of ~0.05 Hz).
Trigger/Charge Direction: Pressing the Trigger/Charge Direction
button will manually trigger the function. It will also control a manual soft
synchronization of the function’s charge direction.

9
Patch Examples
West Coast Synth Voice:
Summary: A sequencer sends voltage to the oscillator while
simultaneously triggering cnōc. The Unipolar Positive output of cnōc
opens the wavefolder, allowing the oscillator signal to pass through.
Audio Path:
• Connect the sine waveform of an oscillator to the audio input of
a wavefolder.
• Monitor the audio output of the wavefolder.
• Set the wavefold amount of the wavefolder to its minimum position.
• Set the symmetry bias of the wavefolder to a desired position.
Output
1V/Oct Signal
Gate Signal

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Control Path:
• Connect the 1V/Oct output of a sequencer to the 1V/Oct input of
the oscillator.
• Connect the gate output of the sequencer to the Signal input.
• Set the Mode toggle to AR Mode.
• Set the Response Curve switch to a desired position.
• Connect the Unipolar Positive output to the CV input of the
wavefolder and set the corresponding CV attenuator to a
desired position.
• Set the Attack and Release faders to desired positions.

11
East Coast Synth Voice:
Summary: A keyboard sends voltage to the oscillator while
simultaneously triggering cnōc. The Unipolar Positive output of cnōc
opens the filter and VCA, allowing the oscillator signal to pass through.
More traditional East Coast patches would incorporate separate cnōc
modules for the filter and VCA.
Audio Path:
• Connect the desired waveform of an oscillator to the audio input of
a filter.
• Connect the audio output of the filter to the audio input of a VCA.
• Monitor the audio output of the VCA.
• Set the fundamental frequency of the oscillator to a desired position.
• Set the cutoff frequency of the filter to a desired position.
• Set the resonance of the filter to a desired position.
• Set the level of the VCA to its minimum position.
1V/Oct Signal
Gate Signal
Output

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Control Path:
• Connect the 1V/Oct output of a keyboard to the 1V/Oct input of
the oscillator.
• Connect the gate output of the keyboard to the Signal input.
• Set the Mode toggle to ASR Mode.
• Set the Response Curve switch to its right position.
• Connect the Unipolar Positive output to a multiple.
• Connect one copy of the cnōc CV signal to the cutoff frequency
CV input of the filter and set the corresponding CV attenuator to a
desired position.
• Connect a second copy of the cnōc CV signal to the CV input of the
VCA and set the corresponding CV attenuator to a desired position.
• Set the Attack and Release faders to desired positions.

13
CV Slew Limiter:
Summary: Adapting the West Coast Synth Voice – A sequencer’s
voltage is slewed through cnōc, creating a portamento (glide) effect
between successive notes.
Audio Path:
• Connect the sine waveform of an oscillator to the audio input of a
wavefolder.
Control Path:
• Instead of connecting the 1V/Octave output of the sequencer
directly to the 1V/Octave input of the oscillator, connect it to the
Signal input of a secondary cnōc.
Output
1V/Oct Signal
Gate Signal

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• Set the Mode toggle to its left position to select ASR Mode.
• Set the Response Curve switch to a desired position. Setting the
switch to its left position to select a linear response curve will yield
more obvious results.
• Connect the Unipolar Positive output to the 1V/Octave input of the
oscillator.
• Set the Attack and Release faders to desired positions. The Attack
fader will set the amount of portamento between ascending notes,
while the Release fader will set the amount of portamento between
descending notes.

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Quadrature Modulation:
Summary: This patch uses two cnōc modules. The first cnōc is set
to generate a one-shot triangle waveform function. A gate signal
generated during the release stage triggers a second cnōc that is also
set to generate a one-shot triangle waveform. A gate signal generated
during the release stage of the second cnōc retriggers the first cnōc.
This method of circular patching creates two triangle waveforms that
are 90 degrees out of phase from one another. Both cnōc modules also
continuously retrigger each other. One triangle waveform controls the
amount of wavefolding while the other triangle waveform the amount of
filtering, creating a quadrature, dual timbral modulation.
Output

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Audio Path:
• Connect the sine waveform of an oscillator to the audio input of
a wavefolder.
• Connect the audio output of the wavefolder to the audio input of
a filter.
• Monitor the audio output of the filter.
• Set the fundamental frequency of the oscillator to a desired position.
• Set the wavefold amount of the wavefolder to a desired position.
• Set the symmetry bias of the wavefolder to a desired position.
• Set the cutoff frequency of the filter to a desired position.
• Set the resonance of the filter to a desired position.
Control Path:
• Set the Response Curve switch of both cnōc’s to their left positions to
select linear response curves.
• Set the Mode toggles of both cnōcs to their left positions to select
AR Mode.
• Set the Attack and Release faders of both cnōc to equal positions to
create triangle waveform functions.
• Set the Stage Gate toggles of both cnōc’s to their right positions to
create gate signals at the Gate outputs during their release stages.
• Connect the Gate output of the first cnōc to the Signal input of the
second cnōc.
• Connect the Gate output of the second cnōc to the Signal input of the
first cnōc.
• Connect the Unipolar Positive output of the first cnōc to the CV input
of the wavefolder to control the amount of wavefolding and set the
corresponding CV attenuator to a desired position.
• Connect the Unipolar Positive output of the second cnōc to the FM
input of the filter and set the corresponding FM attenuator to its
desired position.

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This device meets the requirements of the following standards: EN55032,
EN55103-2, EN61000-3-2, EN61000-3-3, EN62311.
Manual Author: Collin Russell
Manual Design: Dominic D’Sylva