alm-busy-circuits-pip-filter

ALM Busy Circuits Pip Filter

Compact analogue LFO with multi-waveform outputs and VCO mode

4 HP Eurorack module

The Pip LFO is a compact 4HP all-analogue low frequency oscillator with a wide frequency range, voltage control, and multiple simultaneous waveform outputs. It offers both bipolar and unipolar versions of saw, triangle, and sine waves, plus a unipolar square output, and can switch into audio-rate VCO mode with 1V/oct tracking for roughly 5 octaves. Its reset input enables waveform sync and hard sync in VCO mode, making it versatile for modulation, drone synthesis, and rhythmic patching.

Features

  • All analogue oscillator circuit
  • 4HP compact form factor
  • LFO frequency range approximately 0.01Hz to 30Hz
  • VCO mode with audio-rate operation and ultrasonic range
  • 1V per octave tracking over approximately 5 octaves in VCO mode
  • Simultaneous square, saw, triangle, and sine wave outputs
  • Bipolar (+/-5V) and unipolar (0-5V) outputs for saw, triangle, and sine simultaneously
  • Unipolar square output at 0-8V
  • FREQ knob for manual frequency setting
  • CV input for voltage-controlled frequency modulation
  • RESET trigger input resets all waveform cycles
  • Hard sync functionality via RESET in VCO mode

Controls & Jacks (20)

  • Reset— LFO reset trigger input. Resets all waveform cycles; acts as hard sync in VCO mode.
  • Frequency 1
  • Saw Output Bipolar— Bipolar sawtooth wave output oscillating between -5V and +5V.
  • Saw Output Unipolar— Unipolar sawtooth wave output oscillating between 0V and +5V.
  • Square Output— Unipolar square wave output at 0-8V.
  • Freq CV Input— CV input for voltage control of LFO frequency.
  • Frequency 2— Manual LFO frequency setting control. Frequency range approximately 0.01Hz (90s cycle) to 30Hz (0.03s cycle) in LFO mode, or audio range in
  • Triangle Output Bipolar— Bipolar triangle wave output oscillating between -5V and +5V.
  • ▼Res
  • FREQ— Manual LFO frequency setting control. Frequency range approximately 0.01Hz (90s cycle) to 30Hz (0.03s cycle) in LFO mode, or audio range in
  • VCO MODE— Toggles VCO mode. When engaged (indicated by associated LED), the LFO operates at audible frequency range and tracks 1 volt per octave rough
  • FREQ CV— CV input for voltage control of LFO frequency.
  • RST— LFO reset trigger input. Resets all waveform cycles; acts as hard sync in VCO mode.
  • Square Out— Unipolar square wave output at 0-8V.
  • Saw Out Bipolar— Bipolar sawtooth wave output oscillating between -5V and +5V.
  • Saw Out Unipolar— Unipolar sawtooth wave output oscillating between 0V and +5V.
  • Triangle Out Bipolar— Bipolar triangle wave output oscillating between -5V and +5V.
  • Triangle Out Unipolar— Unipolar triangle wave output oscillating between 0V and +5V.
  • Sine Out Bipolar— Bipolar sine wave output oscillating between -5V and +5V.
  • Sine Out Unipolar— Unipolar sine wave output oscillating between 0V and +5V.

How-To Guides

  • Slow Ambient Filter Sweep
  • Analogue Drone Bass
  • Hard Sync Growl
  • Tremolo Effect
  • LFO as Clock Source
  • Vibrato Pitch Modulation
  • Sample-and-Hold Randomness
  • Complex Waveform Blending
  • Tempo-Synced LFO Reset
  • Calibrating V/Oct Tracking

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

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