If you are like me and have problems to switch your sound with headphones in you computer.

Materials' list:
• 1 dual channel switch (for stereo) - Mod. 17203 in this case;
• 3 female P2 (3.5mm) in my case - from old pc sound board;
• 1 mini box - I don't know where I found it :);
• 8 wires - net wire;

Accessories and tools:

Glue;
Sandpaper (#300 and #600);
Drill;
Soldering iron;

I put three female connectors because all my cables/extensions are male. If you prefer, you could use a cable soldered internally.

Step 1: Preparing Wires, Connectors, Switch and Box

Prepare your box making the roles for each connector and the switch, Fig. 1. I put all components reaching the back of the box, so I can glue all of them.

After making the roles, I sanded the box to give it a mat aspect - you could see through it but not clearly, Fig. 3 and 4.

Now we should prepare the switch with the wires, because it is easier if you put the wires in the switch before you put it into the box; remember, you have two independent channels, so use colored wires to keep organized. The third wire color you will use to the GND - I use a green one, Fig. 2 and 5.

For some schemes of those jacks see here.

After all parts are OK, you should glue the connectors and wait to be fixed. Then you easily weld all parts together, Fig. 5

Step 2: Finishing

You could use a metallic box to keep it shielded. But I've tested and I have no noise in this current configuration.

You should test (including with a multimeter) to check the resistance and short-circuit.

TIP: If you build like me, when you turn the switch to the left, you will activate the right out. If you prefer to keep the same side, turn the switch 180º.

I used a double-sided tape to stick it behind the monitor.

TIP 2: You can use the foot monitor to hold your headphone like the last picture. Enjoy!

Comment: I would like to see a monitor with a frontal-bottom output for headphone. All that I see have a back output that is unusual (or unpractical).