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A programmable digital audio processing module based on teensy 4.0
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eurorack digital audio-module dev-kit Join the chat at


what is it

This device is a programmable digital audio processor in a eurorack form-factor. The repository contains source code for a set of circuit- and pcb designs for kicad.

the audio codec circuit originally started as a discussion on quad audio channel outputs and a pcb design integrating teensy and cs42448 from Paul Stoffregen on pjrc forum

  • 600 Mhz ARM cortex m7 microcontroller ( teensy 4.0 ) interfacing the follow components
    • audio: multi-channel audio codec ( 6-in / 8-out 24-bit sound card - CS42448 )
    • analog ins/outs: -10V to 10V 16bit/sample control voltage 8 x inputs and 4 x outputs ( ad7606, ad5754 )
    • display: ST7735 128x128 16bit-color tft display
    • breakouts: - for uSD card, USB host/device, midi in/out, 2 x teensy analog in/out (0 to 3v3 w/protection)
  • 24HP aluminium panel mounted for eurorack case
  • write arduino compatible c/c++ firmware & program using arduino/teensyduino (plus teensy audio library)

Open source software stack

  • All schematics and circuit boards are created using Kicad
  • All mechanical designs are created using FreeCAD


This project is a work-in-progress!

What you can do if you like to see progress with this project?

social media

printed circuit boards


  • 2-layer:
  • teensy4
  • cs42448 audio codec
  • 3 x 6.35mm stereo TRS jack inputs
  • 4 x 6.35mm stereo TRS jack outputs
  • connectors for top and bottom breakout boards

breakout boards

top breakout

  • 2-layer:
  • 3.5mm jack analog inputs/outputs
  • midi in/out,
  • usb device/host,
  • microSD female connector


  • 2-layer:
  • 4 x pots
  • 3 x RGB rotary encoders with switches
  • SAMD21 32bit 48Mhz micro-controller
  • Based on Arduino MKR Zero board (can be programmed through standard arduino ide)
  • Communicates with mainboard via standard serial uart RX and TX lines.

panel design

assembly technical drawings


youtube: Eurorack digital audio modules powered by teensy micro-controller


  • General
    • refactor folders so that footprints, symbols and 3d models (should be shared common amoung project, not board-specific)
  • Breakout board for rotary encoders and pots
    • Order
    • Assemble
    • Software
    • Certify
  • panel
    • measurements
    • design
  • Finalize circuits / boards
  • Testing
    • CS42448 audio codec
    • control voltage input
    • control voltage output
    • usb host/device
    • midi in/out
    • st7735 display
    • sd card extension & adapter
  • Document
    • order & build process
    • software process
  • Firmware
    • Sliced audio loops
    • Midi looping
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