analog vco

analogVco · sources · schema v5

Analog-style oscillator with saw / square / triangle / sine outputs and FM input.

The analog VCO is a classic analog-modeled voltage-controlled oscillator that generates four simultaneous waveforms (sawtooth, square, triangle, sine) on separate outputs, plus a continuous morphing output that sweeps from saw through sine to square driven by the shape parameter. It accepts V/oct pitch CV with coarse/fine tuning controls, audio-rate frequency and phase modulation with depth controls, and hard-sync input for phase-locking to another oscillator. The mental model is a single oscillator core with multiple simultaneous taps (like a hardware Moog VCO) plus an interactive waveform morpher — patch the raw waveforms to filters/mixers, use morph for smooth real-time texture, and chain sync ports for rich polysynth interactions.

the faceplate

9 inputs · 6 outputs · 6 params

about this module

Hover a control, or open the patch panel and hover a jack.

inputs

id	cable	what it does
`pitch`	pitch	V/oct pitch input (0V = C4) that drives the oscillator frequency; modulated by the tune, fine, and FM inputs together to set the final sounding pitch. V/oct pitch CV
`fm`	audio	Audio-rate frequency modulation input (typically an LFO or envelope), scaled by the fmAmount parameter to add wobble, vibrato, or dramatic pitch sweeps without changing the coarse tuning. audio signal
`pm`	audio	Audio-rate phase modulation input (typically an LFO or envelope), scaled by the pmAmount parameter to add timbre modulation and metallic character, especially effective on the square and triangle taps. audio signal
`sync`	audio	Hard-sync input that resets this oscillator's phase to zero on every rising edge, allowing you to lock its waveform to a master oscillator for rich, metallic, or aliased tones. When unpatched, the VCO output is unchanged from a version with no sync port. audio signal
`tune`	cv	CV modulation of the tune parameter (semitones); displaces the coarse pitch knob left/right so an external LFO or sequencer can transpose in whole-step intervals without affecting fine tuning. control voltage (CV); modulates tune (additive offset — ±1 CV sweeps the full range, centered on the knob)
`fine`	cv	CV modulation of the fine parameter (cents); displaces the fine tuning knob left/right for subtle pitch micro-adjustments or vibrato-style modulation around the coarse pitch. control voltage (CV); modulates fine (additive offset — ±1 CV sweeps the full range, centered on the knob)
`fmAmount`	cv	CV modulation of the FM depth; displaces the FM-depth knob left/right to dynamically scale how much the fm input affects the pitch — turn it up to let an envelope open the frequency sweep, or down to tighten it. control voltage (CV); modulates fmAmount (additive offset — ±1 CV sweeps the full range, centered on the knob)
`pmAmount`	cv	CV modulation of the PM depth; displaces the PM-depth knob left/right to dynamically scale how much the pm input affects the phase and timbre — open it up from an envelope to add evolving color. control voltage (CV); modulates pmAmount (additive offset — ±1 CV sweeps the full range, centered on the knob)
`shape`	cv	CV modulation of the morph output waveform (0 = sawtooth, 0.5 = sine, 1 = square); displaces the shape knob left/right so an external LFO, envelope, or sequencer can crossfade the morph output through the three classic waveforms in real time. control voltage (CV); modulates shape (additive offset — ±1 CV sweeps the full range, centered on the knob)

outputs

id	cable	what it does
`saw`	audio	The raw sawtooth waveform (rich harmonic content, bright and buzzy), always sounding at the pitch CV regardless of the shape or morph knob. audio signal
`square`	audio	The raw square/pulse waveform (hollow, woody tone), pulse width set by the pw parameter — use this tap to feed a filter or as-is for bright synth bass. audio signal
`triangle`	audio	The raw triangle waveform (softer than square, more mellow), useful for warmth or blended with other taps through a mixer. audio signal
`sine`	audio	The pure sine waveform (no harmonics, pure fundamental), ideal for clean sub-bass, tone modulation, or as a base mixed with other waveforms. audio signal
`morph`	audio	Continuous morphing output that sweeps from sawtooth (shape = 0) through sine (shape = 0.5) to square (shape = 1) as the shape parameter changes; shaped by the shape knob and its CV input, and reflects any FM/PM modulation in real time. The on-card scope displays this output live so you see the crossfade happening. audio signal
`sync`	audio	Hard-sync output — a one-sample +1 pulse at each cycle boundary (phase wrap) so it can clock another VCO's sync input for chained oscillator interactions or external gear. When unplugged, the sync output is silent. audio signal

params

id	label	range	default	curve
`tune`	Tune	-36..36semi	0	linear
`fine`	Fine	-100..100cent	0	linear
`fmAmount`	FM	-1..1	0	linear
`pmAmount`	PM	-1..1	0	linear
`pw`	PW	0.05..0.95	0.5	linear
`shape`	Wave	0..1	0	linear

controls

control	what it does
Fine	Fine tuning in cents (−100 to +100, one cent = 1/100 of a semitone) — apply a perfectly-tuned unison detune when stacked with another oscillator, or dial in an exact note without coarse octave shifts.
FM	Depth of frequency modulation from the FM input (−1 to +1) — 0 means the fm input has no effect. Positive sweeps pitch upward, negative downward; patch an LFO here to add vibrato or ramp it from an envelope for dramatic pitch drops.
PM	Depth of phase modulation from the PM input (−1 to +1) — 0 means the pm input has no effect. Higher values shift the morph timbre more dramatically per unit of PM signal; use this to add envelope-driven color changes.
PW	Pulse width of the square waveform (0.05 to 0.95, duty cycle) — 0.5 is a perfect square, lower values create thin nasal pulses, higher values create inverted thin pulses. Animate this with an LFO for a classic PWM (pulse-width modulation) sweep.
Wave	Waveform selector for the morph output (0 to 1) — 0 = sawtooth, 0.5 = sine, 1 = square. Knob + CV modulation add together, so a sequencer or LFO can smoothly sweep through all three classic waveforms.
Tune	Coarse pitch in semitones (−36 to +36) — shift the whole oscillator up or down by whole-step intervals. With CV modulation on, knob + CV add together, so a sequencer can select octaves while the knob sets a base pitch.

source

analog-vco.ts on GitHub.