instruo/cs-l

Cs-L

Instruō

A dual analogue oscillator optimised for complex waveform generation, featuring two contrasting discrete-circuit oscillators (sawtooth core and triangle core) normalled to one another, with a wavefolder per oscillator, four-quadrant signal multiplier, symmetry biasing, PWM, a global modulation index bus, and digitally-controlled internal modulation routing.1067

Capabilities 6

Complex Oscillatorcomplex-oscillator
Oscillators are normalled to one another with bi-directional FM, wavefold cross-modulation, and a digitally-controlled internal modulation routing bus (Index).1067
LFOlfo
Oscillator A can be switched to sub-audio LFO range via the LFO Button; it continues to track 1V/octave in LFO mode.1067
Oscillatoroscillator
Two independent discrete-circuit VCOs: Oscillator A (sawtooth core) and Oscillator B (triangle core), each with multiple simultaneous waveform outputs.1067
Ring Modulatorring-modulator
On-board four-quadrant multiplier with selectable Ring Modulation, Half Wave Rectification, or Full Wave Rectification modes; each oscillator's sine is normalled to its Multiply Input.1067
Wavefolderwavefolder
Each oscillator has a dedicated wavefolder driven by its sine waveform, with CV input and attenuverter; the folded output appears at the Final Output jack.1067
Waveshaper / Wavefolderwaveshaper
1067

Jacks 26 (15 in / 11 out)

NameSignalVoltageDescription
Inputs (15)
Hard Sync Inputgate—Resets Oscillator A's cycle on each rising edge. Also resets the LFO when LFO mode is active. Voltage threshold 2.5V.1067
Index CV Inputcv—1067
Multiply Carrier Inputmixed—1067
Multiply Modulator Inputmixed—1067
Osc A 1V/Oct Inputcv—Bipolar 1V/octave pitch CV input for Oscillator A; sums with Coarse and Fine knobs. Bidirectionally normalled to Osc B 1V/Oct when Link is engaged.1067
Osc A FM Inputcv—Bipolar FM CV input for Oscillator A; normalled to Osc B sine output. Scaled by the FM Attenuator. External signal breaks the normal.1067
Osc A PWM CV Inputcv-5V to 5V1067
Osc A Symmetry Bias Inputcv—1067
Osc A Wavefold CV Inputcv—1067
Osc B 1V/Oct Inputcv—1067
Osc B FM Inputcv—Bipolar FM CV input for Oscillator B; normalled to Osc A sine output. Scaled by the FM Attenuator. External signal breaks the normal.1067
Osc B PWM CV Inputcv-5V to 5V1067
Osc B Symmetry Bias Inputcv—1067
Osc B Wavefold CV Inputcv—1067
Soft Sync Inputgate—Soft sync (frequency lock / X-Lock) for Oscillator B; changes triangle core charge direction on clock. Locks to integer multiples of the external signal. Voltage threshold 2V.1067
Outputs (11)
Multiply Outputaudio—1067
Osc A Final Outputaudio—Wavefolded output whose character is shaped by the Wavefold fader and Symmetry Bias Attenuverter.1067
Osc A PWM Outputaudio—1067
Osc A Sawtooth Outputaudio—1067
Osc A Sine Outputaudio—1067
Osc A Triangle Outputaudio—1067
Osc B Final Outputaudio—1067
Osc B PWM Outputaudio—1067
Osc B Sine Outputaudio—1067
Osc B Square Outputaudio—1067
Osc B Triangle Outputaudio—1067

Parameters 26

NameTypeRangeBehavior
Depthknob—Determines the amplitude of the carrier signal in the multiplier. Unity gain is reached when the pointer points approximately at the Multiply Modulator Input (2 o'clock); past that point the multiplied signal clips in a harmonically pleasing way.1067
Indexknob—Simultaneously sets the gain of both internal VCAs that route each oscillator's sine waveform to the modulation bus. Anticlockwise decreases modulation depth; clockwise increases it.1067
Index Attenuverterknob—1067
Index Buttonbutton—Acts as a shift key: holding it illuminates all other buttons to show enabled/disabled modulation routings. Pressing other buttons while held toggles their corresponding internal modulation route.1067
LFO Buttonbutton—Toggles Oscillator A between audio range (unilluminated) and sub-audio LFO range (illuminated white). Oscillator A continues to track 1V/oct in LFO mode; the LFO resets on rising edges at the Hard Sync Input.1067
Link Buttonbutton—When illuminated white, bidirectionally normals 1V/oct CV between oscillators so that patching one input controls both. A second patch on the other input breaks the link and restores independent tracking.1067
Mod Buttonbutton—Controls PWM cross-modulation routing: unilluminated = disabled; white = Osc A sine to Osc B PWM and Osc B sine to Osc A PWM; amber = Osc A sine to Osc B PWM only.1067
Osc A Coarseknob—Controls the fundamental frequency of Oscillator A, determining the pitch of all corresponding waveforms. Clockwise increases frequency; anticlockwise decreases it.1067
Osc A Fineknob—Fine-tunes Oscillator A's fundamental frequency relative to the Coarse knob setting. Clockwise increases frequency; anticlockwise decreases it.1067
Osc A FM Attenuatorknob—Sets the depth of frequency modulation applied to Oscillator A. At full clockwise with exponential FM selected, the FM input tracks approximately 1V/oct.1067
Osc A Lin/Exp Toggleswitch—Selects linear (left) or exponential (right) FM response for Oscillator A's FM input. In exponential mode at full FM Attenuator, the input tracks approximately 1V/oct.1067
Osc A PWMknob—Controls the duty cycle ratio of Oscillator A's pulse waveform. Clockwise increases the +/- ratio; anticlockwise decreases it. Range is set to always produce an audible duty cycle without external CV.1067
Osc A Symmetry Bias Attenuverterknob—Controls DC offset (symmetry bias) applied to the Osc A sine waveform before wavefolding. Center position is calibrated to 0V; anticlockwise applies negative bias, clockwise applies positive bias. Also scales external Symmetry Bias Input signal.1067
Zones
Negative Bias
Positive Bias
  • Negative Bias -100–0%Applies negative DC offset to the sine waveform before wavefolding, shifting harmonic overtone content.1067
  • Positive Bias 0–100%Applies positive DC offset to the sine waveform before wavefolding, shifting harmonic overtone content.1067
Osc A Wavefoldfader—Controls wavefolding depth applied to Oscillator A's sine waveform; output appears at Final Output. Fully left gives near-silence; center gives a sine-like shape; fully right gives rich harmonics.1067
Osc A Wavefold Attenuverterknob—Scales and inverts the CV signal at the Osc A Wavefold CV Input before summing with the fader position.1067
Osc B Coarseknob—Controls the fundamental frequency of Oscillator B, determining the pitch of all corresponding waveforms. Clockwise increases frequency; anticlockwise decreases it.1067
Osc B Fineknob—Fine-tunes Oscillator B's fundamental frequency relative to the Coarse knob setting.1067
Osc B FM Attenuatorknob—Sets the depth of frequency modulation applied to Oscillator B.1067
Osc B Lin/Exp Toggleswitch—Selects linear or exponential FM response for Oscillator B's FM input.1067
Osc B PWMknob—Controls the width of the upper and lower pulses of Oscillator B's stepped triangle waveform. Clockwise increases pulse width; anticlockwise decreases it.1067
Osc B Symmetry Bias Attenuverterknob—1067
Osc B Wavefoldfader—Controls wavefolding depth applied to Oscillator B's sine waveform; output appears at Final Output. Fully left gives near-silence; fully right gives rich harmonics.1067
Osc B Wavefold Attenuverterknob—1067
Ring/AM/Rect Buttonbutton—Cycles through three multiply modes: unilluminated = Ring Modulation (four-quadrant); white = Half Wave Rectification (negative removed); amber = Full Wave Rectification (negative inverted to positive).1067
Sub Buttonbutton—Cycles the octave of Oscillator B's Square Output: unilluminated = fundamental; white = one octave below; amber = two octaves below. Also adjusts the sync signal octave when Sync Button is active.1067
Sync Buttonbutton—Selects internal sync routing: unilluminated = no sync; amber = Osc A sawtooth normalled to Osc B Soft Sync; white = Osc B square normalled to Osc A Hard Sync.1067

Firmware history 0 versions

No firmware history recorded.

References 2

  1. [1067]
    Instruō Cs-L User Manualmanual
    source 1067 canonical ↗ archived ↗
    ● verified 2026-06-01
  2. [1068]
    Instruō Cs-L product pageproduct_page
    source 1068 canonical ↗ archived ↗
    ● verified 2026-06-01