Product status: Active


  • Only 2HP wide
  • 1 MIDI TRS input (Jack 1)
  • 4 MIDI TRS Thru outputs (Jack 2-5)
  • 3 Custom jacks that can be used for up to 3 more MIDI TRS Thru, or used freely by a pinstrip on the backside. (Jack 6-8)
  • 3 Buffered MIDI serial thru outputs 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 indicator for incoming MIDI activity through a hole in the Otto front.

Package contents

  • Module
  • 2 screws
  • 1 Eurorack power cable
  • 1 Sticker sheet
  • Plastic zip bag

The 3 buffered MIDI-THRU (A,B,C) pins on the backside can be used in a number of ways:

  • Extra MIDI THRU outputs, just add connectors.
  • Feed MIDI THRU to other modules MIDI input pins on the backside. Inside your rack.
  • Use A,B and C as “TX” and GND signals to feed your Arduino MIDI project directly to the RX pin.

The module will normally be pre-configured for TRS type A.
You can change this by yourself by changing/resoldering the solderpads.
See the manual below.

No MIDI cables included.

The 3 bottom jacks (6,7 and 8) can be used more freely.
On the back you will find a pinstrip with tip and ring pins for each of these 3 jacks.
There is also some general-purpose GND-pins on the pinstrip.
Here you can connect whatever you like, that you want to get in a stereo jack on the frontpanel, for example MIDI inputs or outputs from other modules.
You can also skip the pins and use the solderpads to configure these jacks for type A or type B MIDI TRS Thru outputs (like jacks 2-5).

Serial number from 110 and above have the addon soldered to the pinstrip and a nice dedicated frontpanel.
On earlier versions with serial number below 110, the addon have a female header and the frontpanel are the same as the Otto Passive Stereo with the numbers 1 to 8.

See youtube video here.

Read more about MIDI here.


890 SEK

Technical specifications


Width: 2 HP
Depth: 42 mm

Current consumption

+12V: 5 mA

Additional files, images and videos

Otto MIDI - User manual

Left view

Right view

Back view