Steady State Fate Zephyr
SSI2130-based complex VCO with 6 waveforms and thru-zero modulation
10 HP Eurorack module
The Zephyr is a 10HP complex analog VCO built around the SSI2130 chip, designed by Steady State Fate in honor of their daughter. It combines the octave-switching precision of the SSF Spectrum VCO with the complex waveform generation of the Zero Point Oscillator. Six simultaneous waveform outputs (Sine, Triangle, Saw, Pulse, Sub, Z-Wave) plus through-zero phase modulation, ZYNC hybrid sync, voltage-controlled wave folding, and flexible FM make it one of the most feature-rich single-voice oscillators in its HP footprint.
Features
- Based on the SSI2130 analog VCO chip — same core used in several high-end boutique designs
- Six simultaneous waveform outputs: Sine, Triangle, Saw, Pulse, Sub, Z-Wave
- True through-zero phase modulation (TZPM) via the ZMOD input — no zero-crossing artifacts
- ZYNC hybrid mode combines reversing hard sync with linear TZPM for unique timbres
- FLIP mode triggers hard waveform reversal from the ZMOD signal
- 8-position octave rotary switch for fast, reliable octave transposition
- Three Tune Range modes: FINE (±1 oct), COARSE (±7 oct), LFO (8mHz–70Hz)
- Dedicated low-distortion Sine output with 0.3–0.6% THD
- PWM with two types: EDGE (asymmetric) and CENTER (symmetric) for different harmonic characters
- Sub output is 1 or 2 octaves below fundamental, character shaped by PWM settings
- Z-WAVE output uniquely blends VC wavefold of overdriven SINE with PWM pulse
- Voltage-controlled wavefold depth via Fold CV input for dynamic Z-WAVE textures
Controls & Jacks (28)
- ZMOD Mode — 3-position switch: TZPM (through-zero phase modulation), ZYNC (hybrid reversing sync), FLIP (hard waveform reversal)
- Tune Range — 3-position switch selects TUNE knob response: FINE (±1 octave), COARSE (±7 octaves), LFO (±7 octaves, switches to LFO mode)
- FM Mode — 2-position switch: EXP (DC-coupled exponential FM response) or LIN (AC-coupled linear FM response)
- PWM Type — 2-position switch: EDGE (asymmetric pulse width, rising edge fixed) or CENTER (symmetric pulse width, centered around midpoint)
- Sub Octave — 2-position switch: SUB-1 (1 octave below fundamental) or SUB-2 (2 octaves below fundamental). Also affected by PWM type and width.
- Octave — 8-position rotary switch selecting oscillator octave range (positions 1–8). Sets the base octave for the VCO across its full audio and LFO f
- Tune — Frequency tuning knob. Response depends on Tune Range switch: FINE (±1 octave), COARSE (±7 octaves), or LFO mode (±7 octaves, sub-audio rang
- Pulse Width — Sets the pulse width of the Pulse output. Works in conjunction with PWM Type switch (EDGE/CENTER). Also affects the Sub output character.
- Z-Wave — Controls the Z-WAVE mix amount — blends VC wave folding of the overdriven SINE with the PWM pulse output. Clockwise increases wavefold depth
- PW Mod — Attenuator for the PWM CV input. Sets the depth of external pulse-width modulation applied to the Pulse (and Sub) outputs.
- FM Level — Attenuator for the FM input. Controls the depth of frequency modulation applied from the FM jack. Works with FM Mode switch for EXP or LIN r
- Fold — Manual wavefold amount control for the Z-WAVE path. Increases the drive into the wavefolder section, adding harmonics to the Z-WAVE output.
- Index — Sets the ZMOD modulation index depth (up to 1.5x modulation depth). Controls how deeply the ZMOD source modulates the oscillator in TZPM or
- Octave LED — Status LED associated with the octave switch section, indicating oscillator activity.
- PWM CV In — CV input for pulse width modulation. Depth controlled by PW Mod attenuator knob. Modulates width of the Pulse and Sub outputs.
- Fold CV In — CV input for the wavefold depth in the Z-WAVE section. Voltage-controls the harmonic content of the Z-WAVE output.
- ZMOD In — Multi-mode modulation input. In TZPM mode: through-zero phase modulation source. In ZYNC mode: hybrid reversing sync + TZPM. In FLIP mode: t
- FM In — Frequency modulation input. AC-coupled (linear) or DC-coupled (exponential) depending on FM Mode switch. Depth set by FM Level attenuator.
- Saw Out — Sawtooth wave output. Standard falling-ramp waveform derived from the SSI2130 triangle core.
- Pulse Out — Pulse/square wave output with variable width. Width set by Pulse Width knob and PWM CV input. PWM Type switch selects EDGE or CENTER mode.
- Sub Out — Sub-octave output, 1 or 2 octaves below the fundamental depending on Sub Octave switch. Character is also affected by PWM type and width set
- Z-Wave CV Out — Z-WAVE secondary output or CV-related Z-wave jack. Outputs the Z-WAVE signal — a blend of voltage-controlled wavefold and overdriven SINE mi
- V/OCT In — 1V/octave pitch CV input. Tracks with high precision across the full frequency range thanks to the SSI2130 core. Standard Eurorack V/OCT sca
- Sine Out — Dedicated sine wave output with 0.3–0.6% THD. Low-distortion sine derived directly from the SSI2130 triangle core with careful shaping.
- Tri Out — Triangle wave output. Linear rising/falling waveform, the fundamental waveform of the SSI2130 core. Clean and symmetrical.
- Z-Wave Out — Main Z-WAVE output. Mixes voltage-controlled wave folding of the overdriven SINE with the PWM pulse for a complex, harmonically rich wavefor
- Sync In — Hard sync input. Universal response — works with any waveform input (sine, triangle, square, etc.). Resets the oscillator cycle for classic
- Index CV In — CV input for the ZMOD modulation index (depth). Voltage-controls the Index VCA, allowing dynamic modulation depth up to 1.5x. Works in all Z
How-To Guides
- Classic PWM Pad
- Through-Zero FM Bass
- Complex LFO Source
- ZYNC Sync Lead
- Wavefold Texture
- Detuned Two-Voice Pad
Explore the interactive Zephyr panel on BleepDex — tap any control to learn what it does.
