expert-sleepers-lorelei

Expert Sleepers Lorelei

Analog VCO with quadrature sines and simultaneous waveshaping

8 HP Eurorack module

Lorelei is a 100% analog VCO using discrete transistor OTAs, offering three simultaneous waveform outputs: square/pulse, sine/pseudo-triangle, and cosine/pseudo-saw. All three outputs are shaped at once by a single waveshape control, which progressively morphs the square toward a triangle and the quadrature sine pair toward triangle/saw-like waveforms. A unique cross-modulation input acts as a voltage-controlled inhibitor rather than a hard sync, giving a wide palette of timbres depending on the waveform and amplitude of the syncing signal.

Features

  • Three simultaneous waveform outputs: square/pulse, sine/pseudo-triangle, cosine/pseudo-saw
  • Single waveshape control morphs all three outputs simultaneously
  • Quadrature (90° phase-shifted) sine outputs enable stereo/rotation patching without extra modules
  • Cross-modulation input gradually inhibits oscillation above ~3.3V — smoother than hard sync
  • X-Mod timbre depends on shape AND amplitude of syncing signal for wide palette of effects
  • Linear FM input for through-zero FM and audio-rate modulation
  • Exponential FM input with dedicated front-panel attenuator
  • Shape CV input with dedicated front-panel attenuator for envelope/LFO waveshape modulation
  • At waveshape midpoint, perceived pitch of sine/cosine outputs doubles due to waveform folding
  • 8-position octave selector switch (white) for coarse register selection
  • Tune knob (blue) adjusts pitch approximately ±1 octave for fine-tuning
  • 100% analog circuit using discrete transistor OTAs throughout

Controls & Jacks (13)

  • V/Oct
  • Lin FM
  • Exp FM
  • X-Mod
  • Shape CV
  • Square Out
  • Sine Out
  • Cosine Out
  • Octave
  • Tune
  • Exp FM Attenuator
  • Shape
  • Shape CV Attenuator

How-To Guides

  • Basic Analog Voice
  • Quadrature Sine Drone
  • Classic Oscillator Hard Sync
  • Waveshape Timbre Modulation
  • Exponential FM Bell Tones
  • X-Mod Pulse Width Exploration

Explore the interactive Lorelei panel on BleepDex — tap any control to learn what it does.

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