Headphones hotswap box

I needed a way to switch my TRRS headphones between my desktop and laptop without digging around for cables. Built a little box for it.

Three TRRS jacks: one for input (the headphones), two for outputs (laptop and desktop). Signal gets routed through a 4P3T rotary switch — one position for each output, and a center-off position for mute/disconnect. Nice to have a hardware kill-switch in the middle.

Used shielded TRRS jacks and wired straight through, no components. Added copper shielding tape to the inside of the enclosure to keep noise out — it helped. The box is aluminium, pocket-sized, with a knurled knob on top. Labelled with a paint pen.

No popping, no weird interference, and I can swap sources without pulling cables. Feels nice to have a physical switch instead of relying on software or dongles. I just have to route 2 TRRS cables, one to the laptop and one to the desktop.

Shopping list

• 3x TRRS 3.5mm jack sockets: here.
• a 4p3t potentiometer here. Having 3 positions, 1 is for each output, and one is disconnected
• some *adhesive** copper tape, like this.
• a knob like this.
• some M2, M3, or self-tapping screws