4ms-looping-delay

4ms Looping Delay

Clock-synced digital delay, looper, and memory scrubber

16 HP Eurorack module

The Looping Delay is a clock-based digital delay and looper for Eurorack that combines sample-accurate delay, infinite looping, and real-time memory scrubbing into a single module. It offers crystal-clear 48kHz/24-bit audio with features like windowing, reverse playback, resonant delay (Karplus-Strong), and sound-on-sound layering for deeply expressive and rhythmically synchronized sound design.

Features

  • 87 seconds maximum delay/loop time in mono mode, 43 seconds in stereo mode
  • 48kHz/24-bit sampling rate, loop stored at 16-bit in 64Mbit volatile SDRAM
  • Crystal-clear digital delay, not a tape or analog emulation
  • Delay and loop time sync-able to internal clock, tapped tempo, or external clock
  • Infinite Hold mode disables recording and plays a static loop
  • Windowing (scrolling/scrubbing) of loop start and end points via Inf. Hold + Feedback knob
  • Reverse mode for backwards playback and recording
  • Feedback ranges from 0% to 110% including blooming echo effect
  • 1V/octave tracking in Unquantized Time Mode for Resonant Delays (Karplus-Strong/Waveguide)
  • Wet/Dry Mix output plus dedicated Send/Return jacks for external effects feedback loop
  • Stereo mode using Return/Send as right channel In/Out
  • CV inputs for Time, Feedback, Delay Feed, and Mix

Controls & Jacks (24)

  • Delay Feed— Record level / input level for signal being recorded into memory (0-100%). Does not affect dry signal.
  • Feedback— Amount of signal read from memory to be written ahead (0-110%). At 100% creates infinite loop. In Inf. Hold mode, enables windowing.
  • Time— Sets the loop/delay time in number of beats, ranging from 1 to 16. Combined with Time switch for extended range.
  • Ping— External clock input for tempo setting.
  • Feedback CV— Control voltage for feedback; enables windowing when Inf. Hold is held.
  • Time CV— Control voltage for time modulation.
  • In— Main audio input. In mono mode: mono input. In stereo mode: left channel input.
  • Reverse— Trigger/gate input to toggle reverse mode.
  • Mix— Crossfade between dry (In jack) and wet (delay/loop) signals on Audio Out. Fully left = dry, fully right = wet.
  • Mix CV— Control voltage for dry/wet mix.
  • Loop Clk Out— Loop/delay time clock output, quantized to sample rate.
  • Send— In mono mode: delay signal for external effects. In stereo mode: right channel output.
  • Audio Out— Main audio output with dry/wet mix. In stereo mode: left channel output.
  • Return— In mono mode: external feedback loop return (effects return). In stereo mode: right channel audio input.
  • Clock Out— Master clock output, synchronized to Ping clock with sample-rate quantization and low jitter.
  • Hold— Trigger/gate input to toggle Infinite Hold mode.
  • Delay Feed CV— Control voltage for record level.
  • Ping Button— Tap to set the base clock tempo. One tap sets one beat. Light indicates button state.
  • Inf. Hold— Toggle between delay mode (off) and looping mode (on). Light indicates current state. In loop mode, start/end points determined by current r
  • Time LED— Red LED that blinks in time with current delay/loop time, providing visual feedback.
  • Reverse Button— Toggle reverse playback direction. Light indicates reverse state. Affects both read and write directions.
  • 1/8
  • Time Switch— Modifies Time knob: Center (=) for 1-16 beats, Up (+16) adds 16 beats, Down (1/8) divides by 8 for eighth notes.
  • Time LED (red)— Red LED that blinks in time with current delay/loop time, providing visual feedback.

How-To Guides

  • Clear Audio Buffer
  • Factory Reset
  • Save System Settings Persistently
  • Classic Rhythmic Echo
  • Karplus-Strong Plucked String
  • Sound on Sound Layering
  • Time Scrubbing and Layer Peeling
  • Granular Scrubbing and Slow-motion
  • Reverse Echoes
  • External Effects in Feedback Path
  • Blooming Echo Swell

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

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