MIDI Addon

Product status: Ended

This is an addon for the Otto Stereo.
You can buy a complete module including the Otto Stereo and this addon here.
You will get a better price when you buy this item complete, than buying the two parts as separate items.


  • Addon for the Otto Stereo Passive.
  • Can also be used without the Otto front if you want to build a MIDI Thru box or if you need opto-coupled MIDI input in your Arduino project.
  • 1 MIDI TRS input (Female header)
  • 7 MIDI TRS Thru outputs (Female header)
  • 3 Buffered MIDI serial thru outputs on a pinstrip on the backside. Can be used as extra THRU outputs.
  • The TRS jacks are preconfigured for MIDI TRS Type A, but can be changed to Type B by changing soldering-pads.
  • LED that shows MIDI activity

If you buy the Otto Stereo and this addon as separate items, then you need to drill a 2mm hole for the LED indicator yourself.

Package contents

  • Addon board
  • 1 Eurorack power cable
  • Plastic zip bag

The addon will be pre-configured for TRS type A for the input and first 4 outputs.
You can change this by yourself by changing/resoldering the solderpads.

No MIDI cables included.

For more information see:

See youtube video here.


390 SEK

Technical specifications


Width: 0 HP
Depth: 0 mm

Current consumption

+12V: 5 mA

Additional files, images and videos

MIDI Addon - User manual

Left view

Right view