Portable Headset + Aux Mixer

Check the ERRATA (second sheet) before implemeting!

Inputs and outputs:

• TRRS Headset connector (passive headphones + mic for voice)
• AUX: Stereo line in (mixed to mono)
  • Mixed into headphones for monitoring
  • Mixed into mixed output for recording/streaming
• TRRS connector for stereo input + mic level mixed output (Aux + Voice)

Designed to be used with a portable guitar amp or other line level device to call into a conference (e.g. Zoom) via a mobile phone. Tested with a standard iPhone Lightning->TRRS adapter.

DISCLAIMER: No warranties or guarantees of any kind. It works for me but it may not work for you. It may destroy your devices. You have been warned. I assume no responsibility for any damanges caused by anyone using or implementing this design.