INSTRUO neóni Through-Zero Oscillator User Manual

INSTRUO neóni Through-Zero Oscillator

Description

FM with tonality! At its core, the Instruō neóni is a traditional analogue oscillator. What sets it apart from other oscillators in the Instruō product line is it’s Through-Zero FM functionality with AC and DC coupled operation. Add that to its precision soft sync and directional hard sync modes, nonlinear wavefolding, internal modulation routings, and you end up with the most tonal FM sounds imaginable.

Unlike traditional FM, where an oscillator momentarily stalls as negative voltage pulls its frequency down to 0 Hz, neóni inverts the polarity of its waveforms until positive voltage pulls it back through 0 Hz.
This behavior allows for complex waveforms with less non-harmonic sidebands. Less clang, more bang!
Drop it all to subsonic territory for organic modulations of morphable voltage.

Features

• Linear through-zero & traditional FM with AC & DC coupled functionality
• Internal modulation routing and general-purpose CV input with attenuator
• Split sawtooth morphing and nonlinear wavefolding
• Precision soft sync
• Directional hard sync
• Individual waveform outputs
• LFO mode

Installation

1. Confirm that the Eurorack synthesizer system is powered off.
2. Locate 12 HP of space in your Eurorack synthesizer case.
3. Connect the 10 pin side of the IDC power cable to the 2×5 pin header on the back of the module, confirming that the red stripe on the power cable is connected to -12V.
4. Connect the 16 pin side of the IDC power cable to the 2×8 pin header on your Eurorack power supply, confirming that the red stripe on the power cable is connected to -12V.
5. Mount the Instruō neóni in your Eurorack synthesizer case.
6. 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: 12 HP
• Depth: 27mm
• +12V: 90mA
• -12V: 90mA

verb (engineering) to adjust an instrument to zero,a point on a scale or instrument from which a positive or negative quantity is reckoned

Key

1. Square Output
2. Sawtooth Output
3. Split Sawtooth
4. Triangle Output
5. Sine Output
6. Wavefold Output
7. Wavefold
8. FM Input
9. FM Attenuator
10. AC/DC Coupled Toggle
11. Traditional/T.Z Switch
12. Hard Sync Input
13. Hard Sync Direction
14. Soft Sync Input
15. Charge Direction Button
16. Signal Router Toggle
17. CV Destination Switch
18. CV Input
19. CV Attenuator
20. Coarse
21. Fine
22. 1V/Oct Input
23. LFO Toggle

Waveforms

Square Output: Square waveform output.
Sawtooth Output: Sawtooth waveform output.

Split Sawtooth: Controls the waveshaping applied to the Sawtooth Output by offsetting from the split at the centre of the wavelength

• When the knob is fully anticlockwise, the sawtooth waveform is at its default phase, frequency, and amplitude.
• Turning the knob towards the centre morphs to a sawtooth waveform at half the amplitude and double the frequency of the original sawtooth waveform.
• Turning the knob fully clockwise morphs to the original sawtooth waveshape but the ramp now starts at a180 degree offset from the original sawtooth waveform.

Triangle Output: Triangle waveform output.
Sine Output: Sine waveform output.

Wavefold Output: Wavefolded waveform output.

• This circuit uses nonlinear wavefolding on neóni’s triangle core and folds between at 10Vpp range, but can expand to ≈14Vpp at its outer range.
• The waveform is determined by the Wavefold fader and (sometimes) the CV Input (See Control Voltage for more information).

Wavefold: Controls the amount of wavefolding applied to the core triangle waveform.

Frequency Modulation & Waveshaping

FM Input: A bipolar control voltage input for the frequency parameter.

• Control voltage is scaled by the FM Attenuator and summed with the values set by the Coarse and Fine knobs.
• The FM Input is linear.
• The polarity of the incoming signal routed to the CV Input (before the signal reaches the FM Attenuator) defines the inversion of the sawtooth waveform.

FM Attenuator: Determines the depth of frequency modulation applied to the fundamental frequency.

• Turning the knob anticlockwise will decrease the depth of frequency modulation.
• Turning the knob clockwise will increase the depth of frequency modulation.

AC/DC Coupled Toggle: Toggles the FM Input between AC coupled and DC coupled operation.

• If set to AC coupled operation, frequency modulation can be more tonal in T.Z. configuration. Any DC offset within the signal connected to the FM Input is filtered out.
• If set to DC coupled operation, frequency modulation can be more clangorous in T.Z. configuration. Any DC offset within the signal connected to the FM Input is present and will offset the fundamental frequency.

Trad/T.Z. Switch: Switches between traditional FM and through-zero FM operation.

• When set to traditional FM operation, neóni behaves similarly to most analog oscillators with linear FM functionality. Pitch-tracking neóni as the carrier within an FM operator changes the pitch of the sound, whereas pitch-tracking the modulator changes the timbre of the sound.
• When set to through-zero FM, more tonal FM functionality is available. Pitch-tracking the modulator within an FM operator changes the pitch of the sound, whereas pitch-tracking the neóni as the carrier changes the timbre of the sound.
• If the Trad/T.Z. Switch is in the down position and the AC/DC Coupled Toggle is in the right position, turning the FM Attenuator will set the oscillator to higher frequencies when no signal is present at the FM Input.

Oscillator Synchronization

Hard Sync Input: All waveform cycles reset on a hard rising-edge signal.
Hard Sync Direction: Controls the behavior of the Hard Sync Input.

When triggered, the core triangle charge will immediately reset to 0V.

If the toggle is in the centre position, the new cycle’s polarity is dictated by the charge direction at the time of sync. A sync signal received during the triangle’s ascending ramp will reset to a new positive charge from 0V. A sync signal received during the triangle’s descending ramp will reset to a new negative charge from 0V.

If the toggle is in the up position the core triangle charge will always reset to a positive charge from 0V, regardless of the ramp direction at the time of synchronization.

If the toggle is in the down position the core triangle charge will always reset to a negative charge from 0V regardless of the ramp direction at the time of synchronisation.

Soft Sync Input: neóni’s core triangle changes its charge direction on a hard rising edge signal.

Charge Direction Button: Controls a manual soft synchronization of the core triangle waveform’s charge direction.

Control Voltage

Signal Router Toggle: Routes the signal present at the Signal Router Toggle: Routes the signal present at the FM Input to different parts of the circuit. Incoming signals will always modulate the frequency of neóni (when unattenuated), regardless of the toggle position.

• If the toggle is in the left position, the positive portion of the incoming signal is clipped and then routed to the Hard Sync Input. This can help stabilize the organic nature of through-zero FM.
• If the toggle is in the centre position, additional routing is disabled.
• If the toggle is in the right position, the incoming signal will be routed to the CV Input before the signal reaches the FM Attenuator. This allows the incoming signal to be connected to the FM Input to be scaled by the FM Attenuator (for frequency modulation) and the CV Attenuator (for general-purpose modulation). The additional parameter controlled is selected by the CV Destination Switch Connecting a signal to the CV Input will break the normalled routing from the FM Input.

CV Destination Switch: Sets the modulation destination for the CV Input to either wavefold amount or split sawtooth waveshaping.
CV Input: The CV Input is a bipolar control voltage input that can control either the wavefold amount or the split sawtooth waveshaping based on the position of the CV Destination Switch.

• Control voltage is scaled by the CV Attenuator and summedwith the value set by either the Wavefold fader or the SplitSawtooth knob. n
• If the CV Destination Switch is in its down position (making wavefold amount the target parameter) and the Wavefold fader isset anywhere below 90%, negative CV will mute the Wavefold Output.
• Control voltage can push either parameter past their maximum manual control range.

CV Attenuator: Determines the depth of modulation applied to the currently selected CV destination.

• Turning the knob anticlockwise will decrease the depth of modulation.
• Turning the knob clockwise will increase the depth of modulation.

Frequency/Pitch

Coarse: The Coarse knob controls the fundamental frequency of the oscillator. It determines the pitch of all waveforms.

• Turning the knob anticlockwise will decrease the frequency.

• Turning the knob clockwise will increase the frequency.
  Fine: The Fine knob is used for minute control of the oscillator’s fundamental frequency and is relative to the frequency value set by the Coarse knob. It also determines the pitch of all waveforms.

• Turning the knob anticlockwise will decrease the frequency.

• Turning the knob clockwise will increase the frequency.
  1V/Oct Input: The 1V/Oct Input is a bipolar control voltage input that is calibrated to 1 volt per Octave.

• This is traditionally used for frequency control (musical pitch) sent from a sequencer or keyboard.

• Control voltage is summed with the values set by the Coarse and Fine knobs.

LFO Toggle: The LFO Toggle enters LFO Mode turning neóni into a fully- functional low frequency oscillator. LFO Mode forces all waveform outputs to oscillate within subsonic frequency ranges.

Patch Examples

East Coast Synth Voice:

Summary: The sequencer or keyboard sends voltages to neóni while simultaneously triggering the envelope generator. The CV output of the envelope generator opens a filter and VCA, allowing neóni to pass through. More traditional East Coast patches would incorporate separate envelope generators for the filter and VCA.

Audio Path:

• Set the LFO Toggle of neóni to its up position, so that it oscillates at audio rate.
• Set the Trad/T.Z. Switch of neóni to its up position, so that traditional FM operation is selected.
• Connect the Sawtooth Output of neóni 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 neóni to a desired position using the Coarse and Fine knobs.
• Set the cutoff frequency of the filter to a desired position.
• Set the resonance of the filter to a desired position.
• Set the gain of the VCA to its minimum position if applicable.

Control Path:

• Connect the 1V/Oct output of a sequencer or keyboard to the 1V/Oct Input of neóni.
• Connect the gate output of the sequencer or keyboard to the trigger input of an envelope generator.
• Connect the CV output of the envelope generator to a multiple.
• Connect one copy of the envelope generator CV signal to the CV input of the filter and set the corresponding CV attenuator to a desired position.
• Connect a second copy of the envelope generator CV signal to the CV input of the VCA and set the corresponding CV attenuator to a desired position.
• Set the envelope stages to desired positions.

Traditional FM:
Summary: A secondary oscillator modulates the frequency of neóni In this setup, neóni is the carrier and the secondary oscillator is the modulator. Sequencing or key tracking neóni will change the pitch of the sound. Experiment with different carrier: modulator ratios by changing the frequencies of both oscillators.
Experiment with the AC/DC Coupled Toggle to hear the differences in tone.

Audio Path:

• Monitor the Sine Output of neóni.
• Set the LFO Toggle of neóni is in the up position, so that it oscillatesat audio rate.
• Set the Trad/T.Z. Switch of neóni to its up position, so that  traditional FM operation is selected.
• Tune the Coarse knob and the Fine knob of neóni to desired positions.

Control Path:

• Set the Signal Router Toggle to its centre position, so that internalsignal routing is disabled.
• Connect an audio rate sine waveform to the FM Input of neóni  andset the FM Attenuator fully clockwise.

Through-Zero FM:
Summary: A secondary oscillator modulates the frequency of neóni.
In this setup, neóni is the carrier and the secondary oscillator is the modulator. Sequencing or key-tracking the modulator will change the pitch of the sound. Experiment with different carrier:modulator ratios by changing the frequencies of both oscillators. Experiment with the AC/
DC Coupled Toggle to hear the differences in tone.

Audio Path:

• Monitor the Sine Output of neóni.
• Set the LFO Toggle of neóni is in the up position, so that it oscillates at audio rate.
• Set the Trad/T.Z. Switch of neóni to its down position, so thatthrough-zero FM operation is selected.
• Tune the Coarse knob and the Fine knob of neóni to  desired positions.

Control Path:

• Set the Signal Router Toggle to its centre position, so that internalsignal routing is disabled.
• Connect an audio rate sine waveform to the FM Input of neóni  and set the FM Attenuator fully clockwise.

Sawtooth Polarity Switch:
Summary: If the sawtooth waveform is used, connecting negative CV to the FM Input will change the polarity of the sawtooth waveform, regardless of the FM Attenuator’s knob position. A threshold comparator selects the polarity of the sawtooth wave. The polarity can be switched at audio rate for hard sync-style effects.

Audio Path:

• Monitor the sawtooth waveform via an oscilloscope and an audio output.

Control Path:

• Set the AC/DC Coupled Toggle to a desired position. The setting will have smoother polarity switching than the DC setting.
• Connect a bipolar LFO or a bipolar audio signal to the FM Input.
• Set the FM Attenuator to a desired position, this will change the timbre of the polarity-switched sawtooth waveform.

Through-Zero Oragami:
Summary: The modulator within the FM operator is connected to both the FM Input and the wavefold parameter. Timbre is determined by the pitch and wavefold parameters as well as the FM Attenuator and CV Attenuator.

Audio Path:

• Create an East Coast Synth Voice patch using the Wavefold Output of neóni.

• Set the Wavefold fader of neóni to its minimum position.

• Tune the Coarse knob and the Fine knob of neóni to 11:00 and 12:00, respectively.
  Control Path:

• Set the AC/DC Coupled Toggle to its left position, so that ACcoupled FM operation is selected.

• Set the Signal Router Toggle to its right position, so that the real signal routing from the FM Input is enabled for the CV Input.

• Set the CV Destination Switch to its down position, so that incoming signal at the FM Input will modulate the wavefold amount.

• Connect and audio rate sine waveform of a secondary oscillator to the FM Input and set the FM Attenuator to around 2:00.

• Set the CV Attenuator to its fully clockwise position.

Feedback Seagulls:
Summary: The Sine Output feeds back into the wavefolder amount parameter and the Wavefold Output feeds back into the FM Input.
Moving the Coarse knob and the Wavefold fader will affect the “bird activity.”

Audio Path:

• Set the LFO Toggle to its up position, so that neóni oscillates at audio rate.
• Set the Trad/T.Z. Switch of neóni to its up position, so that traditional FM operation is selected.
• Set the Coarse knob to between 1:00 and 2:00.
• Set the Fine knob to its centre position.
• Monitor the Triangle Output.

Control Path:

• Set the AC/DC Coupled Toggle to its left position, so that ACcoupled FM operation is selected.
• Set the CV Destination Switch to its down position, so that incoming signal at the CV Input will modulate the wave fold amount.
• Set the Signal Router Toggle to its centre position, so that no additional routing is applied.
• Connect the Sine Output to the CV Input.
• Set the Wavefold fader around 75%.
• Connect the Wavefold Output to the FM Input.
• Set the FM Attenuator to its fully clockwise position.

Chug-Chug

Summary: The sawtooth and wave folded waveforms of neóni are mixed in lìon. The output of lìon as well as a stepped triangle waveform from Cš-L are further mixed via the input and inverting input of I-ō47. The
low pass output of I-ō47 is sent through the bottom channel of vincâ.
The output of vincâ is sent through tanh[3]. A sub-square waveform from Cš-L is through-zero frequency modulating and hard synchronizing neóni. A sequencer or keyboard modulates the pitch of neóni and Cš-L. The sequencer or keyboard also triggers cèis. cèis modulates the cutoff frequency of I-ō47 and the level of vincâ. Because Cš-L through zero frequency modulates and hard synchronized neóni, changing the frequency of Cš-L will change the pitch of the sound and changing the frequency of neóni will change the timbre.

Audio Path:

• Set the LFO Toggle of neóni to its up position, so that it oscillates at audio rate.
• Set the Trad/T.Z. Switch of neóni to its down position, so that through-zero FM operation is selected.
• Set the Hard Sync Toggle of neóni to its centre position, so that hard synchronization happens on every up and down charge direction.
• Set the Split Sawtooth knob of neóni to its fully anticlockwise position, so that the sawtooth waveform is at its default setting.
• Set the Wavefold fader of neóni to its centre position.
• Tune the Coarse knob and the Fine knob of neóni to 9:00 and 12:00, respectively.
• Connect the Sawtooth Output and the Wavefold Output of neóni to two inputs of lìon and connect the corresponding pin cables to mix them to a single output.
• Connect the output of lìon to the input of I-ō47 and connect the stepped triangle output of Cš-L to the inverting input of I-ō47.
• Tune Cš-L to around 98 Hz (G2) or a note within this octave.
• Set the stepped triangle’s PWM knob to its center position.
• Set the gain fader of I-ō47 to its maximum level.
• Set the limiter toggle of I-ō47 to its up position
• Set the coarse cutoff frequency knob and the fine frequency knob of I-ō47 to 11:00 and fully anticlockwise, respectively.
• Set the resonance knob of I-ō47 to 9:00.
• Set the feedback toggle of I-ō47 to its down position to disable self oscillation of the resonance.
• Connect the low pass output of I-ō47 to vincâ.
• Set vincâ to fully linear
• Set vincâ’s amplitude/CV attenuator to around 75%.
• Connect the output vincâ to tanh[3].
• Set the level knob of tanh[3] to its maximum position.

Control Path:

• Set the AC/DC Coupled Toggle to its left position, so that AC coupled FM operation is selected.
• Set the Signal Router Toggle to its left position, so that the incoming signal at the FM Input is clipped and routed to the Hard Sync Input.
• Press the sub button of Cš-L so that it illuminates white and the square wave is one octave below the stepped triangle waveform.
• Connect the sub square output of Cš-L to the FM Input of neóni and set the FM Attenuator fully clockwise. The sub square waveform is now through-zero frequency modulating and hard synchronizing neóni.
• Connect the 1V/Oct output of a keyboard or sequencer to the 1V Oct Inputs of neóni and Cš-L.
• Connect the gate output of the sequencer or keyboard to the trigger input of cèis.
• Connect the CV output of cèis to a multiple.
• Connect one copy of cèis’s CV signal to the CV input of I-ō47 and set the corresponding CV attenuator to 2:00.
• Connect a second copy of cèis’s CV signal to the bottom channel CV input of vincâ.
• Set the gate/trig toggle of cèis to its down position.
• Set the shape knob of cèis to 3:30.
• Set the individual stages of cèis (attack to its minimum position, decay to 20%, sustain to 20%, and release to 30%).

Manual Author: Collin Russell
Manual Design: Dominic D’Sylva

This device meets the requirements of the following standards: EN55032,
EN55103-2, EN61000-3-2, EN61000-3-3, EN62311.

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