Switching to analog audio in Ubuntu

[joey]

I'm running the most recent Ubuntu Xenial image by longsleep. I'm just playing around with all the ports, and I see on the Euler bus, there is a pin for EAROUT_N. I assumed that was for headphones, so I wanted to try sending audio to that. I enabled the universe repository and got mplayer installed, and it seems to be playing the audio file I am testing with, but I get no audio out of my headphones. I have the Pine connected to a monitor without speakers, so I don't get any audio through the HDMI, though I assume that's where the audio is being sent to. I found some documents that said I can use amixer to switch to analog audio, but I can't figure out if what I am providing to it is even valid information. Has anyone got audio coming out of their headphone jack in this build of Ubuntu yet? I've never been good with the audio side of things in Linux.