[dsdragon83]

I used the existing jack to find the pin out then unsoldered it and fit a 3.5mm jack in. With the jack I used I had to enlarge the hole the cable goes in a little. I used epoxy putty to fix the jack in place. On mine both of the red cables are ground. Here are a few pics.

 

[TheOmegaCarrot]

Does anyone know why the headphone end of the cable is a TRRS instead of a TRS?

 

[dsdragon83]

The headphone side is wire for a balanced connection but for some reason the cable they provided combines the ground into a standard TRS.