stereovca

stereovca · utilities

Stereo VCA + ring modulator. Per-channel multiply: out_l = in_l * (strength_l + offset) * level; out_r = in_r * (strength_r + offset) * level. The same math behaves as VCA gain control when strength is slow (CV / LFO / envelope) and as ring modulation when strength is audio-rate — no mode toggle, the perceptual difference emerges from signal content. INDEPENDENT normalling: if in_r is unpatched it copies in_l (mono → stereo); if strength_r is unpatched it copies strength_l (one strength drives both VCAs). The two halves normal independently, so true-stereo audio + mono strength works, as does mono audio + per-side strength. Audio carriers (in_l/in_r) declare cable type `audio`; strength inputs declare `cv` (raw bipolar carrier consumed in the multiply with no scaling — listed in PASSTHROUGH_BY_DESIGN) so any cv source (LFO, ADSR, sequencer step CV) lands without a cross-type cast.

A dual (stereo) voltage-controlled amplifier that doubles as a ring modulator — no mode switch, the behavior is purely a function of how fast the control signal is. Each channel computes out = in × (strength + offset) × level: when the STRENGTH input is slow (an LFO, an envelope, a sequencer step) it acts as a VCA, gating and shaping the audio's volume; when STRENGTH is audio-rate it acts as a ring modulator, multiplying two audio signals into clangorous sum-and-difference tones (this matches the hardware truth that 'CV is just slow audio'). The two channels share the LEVEL and OFFSET knobs but have independent audio and strength inputs, with smart normalling so you can drive both sides from one cable: leave IN R unpatched and it mirrors IN L (mono in, stereo out), leave STRENGTH R unpatched and it mirrors STRENGTH L (one modulator drives both VCAs). The STRENGTH inputs take raw bipolar CV directly with no scaling.

the faceplate

4 inputs · 2 outputs · 2 params

about this module

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

inputs

id	cable	what it does
`in_l`	audio	Left audio carrier — the signal the left channel multiplies by its strength. For ring modulation patch an audio oscillator here. audio signal
`in_r`	audio	Right audio carrier. If you leave this unpatched it is normalled to IN L, so a single mono source fans out to both output channels (mono-to-stereo). audio signal
`strength_l`	cv	Left multiplier / modulator (raw bipolar CV, consumed with no scaling). A slow signal makes the channel behave as a VCA (volume control); an audio-rate signal makes it a ring modulator. At strength +1 (and offset 0) the channel passes at unity; at 0 it mutes; negative values invert. control voltage (CV)
`strength_r`	cv	Right multiplier / modulator. If unpatched it is normalled to STRENGTH L, so one CV or LFO controls both VCAs at once; patch it for independent left/right modulation. control voltage (CV)

outputs

id	cable	what it does
`out_l`	audio	Left result: in_l × (strength_l + offset) × level. Audio (or ring-mod) out for the left channel. audio signal
`out_r`	audio	Right result: in_r × (strength_r + offset) × level, honoring the IN R and STRENGTH R normalling above. audio signal

params

id	label	range	default	curve
`level`	Level	0..1	1	linear
`offset`	Offset	-1..1	0	linear

controls

control	what it does
Level	Master output gain applied after the per-channel multiply (0 to 1, default unity) — a final trim on both channels at once without touching the modulation depth.
Offset	A bipolar DC term added to each strength signal before multiplying (-1 to +1, default 0). It sets the QUIESCENT FLOOR — the gain the channel has with nothing patched into STRENGTH — and the dial is marked with that floor's three named waypoints: MUTE at the centre, UNITY at +1, and INV at -1 (also unity, with the polarity flipped, so the two ends differ in phase and not in level). The shipped default is the centre, so a freshly patched stereovca with no modulator is SILENT until you move this control or send it some strength; turn it up toward +1 to lift the floor so the channel stays open at unity even with no modulator, and a strength signal then only ducks it — handy for 'always on with optional duck' patches. With a cable in STRENGTH the gain is (strength + offset) x level, so the marks name where this dial sits rather than how loud the module is.

control

what it does

Level

Master output gain applied after the per-channel multiply (0 to 1, default unity) — a final trim on both channels at once without touching the modulation depth.

Offset

A bipolar DC term added to each strength signal before multiplying (-1 to +1, default 0). It sets the QUIESCENT FLOOR — the gain the channel has with nothing patched into STRENGTH — and the dial is marked with that floor's three named waypoints: MUTE at the centre, UNITY at +1, and INV at -1 (also unity, with the polarity flipped, so the two ends differ in phase and not in level). The shipped default is the centre, so a freshly patched stereovca with no modulator is SILENT until you move this control or send it some strength; turn it up toward +1 to lift the floor so the channel stays open at unity even with no modulator, and a strength signal then only ducks it — handy for 'always on with optional duck' patches. With a cable in STRENGTH the gain is (strength + offset) x level, so the marks name where this dial sits rather than how loud the module is.

source

stereovca.ts on GitHub.