If you just want the schematics and files, go here.
This project started with my simple desire to have a chonky hardware switch to go between headphones and speakers on my main rig. I was sick of software getting in my way of swapping output devices, so I turned to hardware.
Along the way I found a device that would convert "4 post" audio output to 3.5mm headphone jack. It was $300. Apparently audiophiles are all about that markup. So... I did what any enterprising person woudl do, and hacked together a device.
The board is version three, as the first version was just a bunch of wires soldered together as a sort of harness. Version two was on a breakout board, using smaller and higher quality resistors. Janky, but it worked. Then, my buddy told me that I should make it into a PCB, and slap it on a SAO for Defcon 30. Never having done anything like that before, I sai alright!
So, deep in the woods one Tuesday afternoon, with a laptop and guidance from him, we made a beautiful schematic. I generated all the files, and this was the result.
It is a strange feeling to take something from idea, all the way through to final product. Obviously, this needs a case of some kind. But... the electronics are sound.
If you are tring to complete the SAO to use it in a audio setup the size of the Resistors on R1, R2, R3 & R4 go here. R5 is just for connecting to a ground plane, and you can use whatever resistor you want (I use a "0"). Please feel free to reach out if you have questions or concerns.