Oscillators

SINE

A pure sine VCO. One knob, one input, one output. Nothing to get wrong.

What is a SINE?

A pure sine voltage-controlled oscillator: one knob, one input, one output. The simplest possible reduction of a VCO. A sine wave is a single harmonic, no overtones, the building block of every other sound in synthesis. Use it as a clean bass fundamental, an FM carrier or modulator, or as the reference shape when teaching the harmonic series ("a sine is one harmonic; everything else is layered sines"). When you outgrow it, the full VCO adds simultaneous TRI/SAW/SQR outputs, FM, PWM, and sync.

In a patch

Patch SIN out into a VCA or directly into Output to hear the cleanest tone in synthesis - no harmonics, no buzz. For a melody, patch a sequencer or quantizer into V/Oct (1V = one octave). The TUNE knob sets the octave/interval when V/Oct is at 0V (default = C4 = 261.6Hz). Two SINE modules detuned by a few semitones (one at +0, one at +7) make a clean fifth interval; layer with a SAW for a thicker bass with a pure low end. SINE is also the canonical FM carrier - patch the output of another VCO into a VCA, then into your sine pitch source via a mixer for "bell" / "metallic" tones (the full VCO is required for true FM input though).

Inputs

V/Oct (cv) — Pitch input. 1V = one octave (1V/Oct standard). 0V = C4 (261.6Hz), 1V = C5, -1V = C3, etc. Patch a sequencer (SEQ8 row out), a quantizer, or a MIDI-In CV to play melodies. Add to TUNE: at TUNE=0, V/Oct=1V plays C5; at TUNE=+7, V/Oct=1V plays G5. Negative voltages drop pitch below C4.

Outputs

SIN (audio) — Sine wave output, +/-5V audio (Eurorack standard). Pure fundamental, no harmonics. Use as a clean bass fundamental, an FM carrier (mix into another VCO's FM input), or as the reference shape when teaching the harmonic series. Patch directly into a VCA, into the Output module, or layer through Mixer8 with other waveforms.

Controls

TUNE — Tune in semitones. Range +/-24 (two octaves up or down). Sets the pitch when V/Oct is 0V (default = C4 = 261.6Hz). Step in 12ths for octaves (-12 = C3, +12 = C5, +24 = C6). Add the V/Oct input on top: at TUNE=+12, a V/Oct of +1V plays C6. Linear semitone scale - matches the full VCO's coarse knob exactly.

Inspired by

The single-shape sibling of the full VCO. Beginners reach for it when they want a pure sine - bass fundamentals, FM carriers, or comparing timbres against the SAW/TRI/SQR siblings without fiddling with a waveform selector.

Doepfer A-110-4
Moog 921 (sine voice)

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