KNELL(1)             DEAD MEDIUM SIGNAL REGISTRY             KNELL(1)

NAME
     DM-01 KNELL -- Sample Player

STATUS
     Active: yes
     Revision: 02
     First logged: 2026.09.14

DESCRIPTION
     KNELL is a compact Eurorack sample player built around the Raspberry Pi Pico. It holds a bank of audio samples baked directly into the module's memory; no SD card, no loading screens. When it receives a trigger (from a gate signal or the front panel button), it plays the selected sample once through, like a drum hit or a stab.
  
  Pitch is continuously variable via a knob and a CV input. A second CV input controls which sample plays at trigger time, allowing for sequenced playback patterns. Hold one of the front panel buttons and it auto-scrolls through the sample bank so you can audition sounds quickly. The small OLED display shows the sample name and a waveform thumbnail so you always know what you're working with at a glance.

  The result is a small, self-contained voice that can cover drum hits, one-shot melodic samples, percussive stabs, or any other short sound, and that responds to CV in ways that make it musically useful in a modular context.

  Note that KNELL is not a sample recorder; it cannot record new samples. It is a playback-only device, and the sample bank is fixed at build time. The sample bank is open-source and can be modified by anyone with the right tools, but the module itself cannot be used to record new audio.

  When I created KNELL, I wanted a simple and fun sample player that used as many of the RP2040's built-in features as possible. Its PWM-based audio output is deliberately lo-fi, and since it uses the RP2040's onboard ADC to read incoming CV signals, its pitch accuracy is poor. I find that despite these limitations, KNELL is a fun and useful module that can add a lot of character to a modular setup. It is not a high-fidelity sample player, but it is a playful and expressive one.


SPECIFICATIONS
     Width ..............  6HP
     Depth ..............  --mm
     Current ............  +12V: --mA / -12V: --mA
     CV input range .....  0-5V
     Pitch accuracy .....  +/-0.5 cent / 5 octaves
     MCU ................  RP2040 / RP2350

     Modes ..............  QUANTIZER / VCO

ACQUISITION
     Assembled unit .....  [storefront]
     Build documentation  [build guide]
     Source .............  [github]

CHANGELOG
     2026.09.14   REV 01   Initial release. Quantizer mode only.
     2026.11.02   REV 02   VCO mode added. DAC output buffer revised.
                           LED driver moved to 74HC595.

DEAD MEDIUM                  2026.11.02                          CAIRN(1)