Instruo Cs-L
Dual-core complex oscillator for West Coast harmonic mayhem
26 HP Eurorack module
The Instruo Cs-L is a dual analogue oscillator module combining a sawtooth-core oscillator (Osc A) and a triangle-core oscillator (Osc B) with extensive cross-modulation capabilities rooted in West Coast synthesis philosophy. It features per-oscillator wavefolders, a four-quadrant multiplier, internal VCA-controlled modulation routing, oscillator sync, and a global Index bus for simultaneous modulation depth control. The result is an instrument capable of generating extraordinarily rich, harmonically complex timbres far beyond traditional subtractive synthesis.
Features
- Two independent contrasting-core analogue oscillators: sawtooth core (Osc A) and triangle core (Osc B)
- Per-oscillator wavefolder with CV input and attenuverter, normalled to oscillator sine waveforms
- Per-oscillator symmetry bias with CV input and attenuverter for DC offset before wavefolding stage
- Four-quadrant multiplier/amplitude modulator with ring, half-wave rectification, and full-wave rectification modes
- Global Index modulation bus with two internal linear VCAs controlling up to 6 internal modulation routings simultaneously
- Digitally-controlled internal modulation routing via Index Button shift functions
- Bidirectional 1V/Oct linking via Link Button
- Hard Sync Input for Oscillator A (rising edge resets cycle, threshold 2.5V)
- Soft Sync Input for Oscillator B (frequency lock/X-lock, threshold 2V)
- Internal sync routing: Osc A sawtooth to Osc B soft sync, or Osc B square to Osc A hard sync
- LFO mode for Oscillator A (sub-audio frequencies, retains 1V/Oct tracking, resets on Hard Sync)
- Sub square modes for Oscillator B: fundamental, -1 octave, -2 octaves
Controls & Jacks (53)
- LFO — Switch Oscillator A to sub-audio LFO range frequencies
- Osc A Fine Frequency — Fine frequency control for Oscillator A
- Osc A PWM CV Input — CV input for PWM control of Oscillator A
- Osc A PWM Output — Pulse width modulation waveform output from Oscillator A
- Osc A Sine Output — Sine waveform output from Oscillator A
- Osc A 1V/Oct Input — 1V/Octave pitch control input for Oscillator A
- Osc A Coarse Frequency — Coarse frequency control for Oscillator A (sawtooth core)
- Osc A Wavefold CV Input — CV input for wavefold amount on Oscillator A
- Osc A PWM — Pulse width modulation duty cycle control for Oscillator A
- Mod — Routes Index-controlled sine waveforms to PWM CV inputs. White: bidirectional cross-modulation. Amber: Osc A to Osc B only.
- Osc A Triangle Output — Triangle waveform output from Oscillator A
- Hard Sync Input — Hard sync trigger input for oscillator synchronization
- Ring — Selects amplitude modulation mode for the Multiply circuit. Cycles through Ring Mod, Half-Wave Rect, and Full-Wave Rect.
- Wavefold A — Controls the amount of wavefolding on Oscillator A. Center is sine-like; fully right adds rich harmonics.
- Osc A Sawtooth Output — Sawtooth/Ramp waveform output from Oscillator A
- Osc A FM Input — Frequency modulation input for Oscillator A
- Osc A FM Attenuator — Frequency modulation depth attenuator for Oscillator A
- Index — Global modulation index control for internal routing
- Multiply Mix — Controls the blend between the multiplied signal and direct oscillator output.
- Multiply CV Atten — Attenuates external CV going to the Multiply section.
- AM — Selects amplitude modulation mode for the Multiply circuit. Cycles through Ring, Half-Wave Rect, and Full-Wave Rect modes.
- Multiply Modulator Input — Modulator signal input for four-quadrant multiplication
- Osc A Final Output — Final waveform output from Oscillator A (after wavefold and symmetry bias)
- Osc A Lin/Exp — Toggle between linear and exponential FM response for Oscillator A
- Osc B Lin/Exp — Toggle between linear and exponential FM response for Oscillator B
- Index CV Input — CV input for global modulation index control
- Index Mode — Displays current Index routing states when held. Shows which modulation destinations are active.
- Osc B Symmetry Bias Input — CV input for waveform symmetry biasing on Oscillator B
- Osc A Symmetry Bias Input — CV input for waveform symmetry biasing on Oscillator A
- Depth — Controls the output level of the Multiply circuit. Unity gain at approximately 2 o'clock; beyond adds harmonic clipping.
- Multiply Output — Output of four-quadrant multiplication/amplitude modulation
- Osc B FM Input — Frequency modulation input for Oscillator B
- Osc B FM Attenuator — Frequency modulation depth attenuator for Oscillator B
- Index Attenuverter — Attenuverter for index CV input
- Sub Mix — Controls the mix level of the sub-octave square signal from Oscillator B.
- Multiply Depth Atten — Attenuates external CV input for the Multiply Depth parameter.
- Multiply Carrier Input — Carrier signal input for four-quadrant multiplication
- Osc B Final Output — Final waveform output from Oscillator B (after wavefold and symmetry bias)
- Osc B Fine Frequency — Fine frequency control for Oscillator B
- Wavefold B — Controls the amount of wavefolding on Oscillator B. Center is sine-like; fully right adds rich harmonics.
- Osc B Triangle Output — Triangle waveform output from Oscillator B
- Osc B 1V/Oct Input — 1V/Octave pitch control input for Oscillator B
- Osc B Coarse Frequency — Coarse frequency control for Oscillator B (triangle core)
- Osc B Wavefold CV Input — CV input for wavefold amount on Oscillator B
- Osc B PWM — Pulse width modulation duty cycle control for Oscillator B
- Osc B Wavefold — Selects the octave of Oscillator B square output. White: -1 octave. Amber: -2 octaves.
- Osc B Square Output — Square waveform output from Oscillator B
- Link — Link Oscillators A and B for parallel frequency tracking
- Sync — Select synchronization mode (hard sync or soft sync)
- Soft Sync Input — Soft sync audio input for oscillator synchronization
- Osc B PWM CV Input — CV input for PWM control of Oscillator B
- Osc B PWM Output — Pulse width modulation waveform output from Oscillator B
- Osc B Sine Output — Sine waveform output for Oscillator B
How-To Guides
- Classic West Coast FM Drone
- Wavefold Timbre Sculptor
- Hard Sync Lead
- Ring Modulation Clangour
- Gentle LFO Vibrato
- Evolving Index Modulation Pad
- Multiplier as Voltage Controlled Amplifier
- Formant Synthesis Voice
- Bonnie Racket FM Chaos Voice
- External Signal Wavefolder
Explore the interactive Cs-L panel on BleepDex — tap any control to learn what it does.
