Hey, So last month I bought a 13" rMBP (now running Yosemite 10.10.1) and yesterday while trying out a subwoofer I got, it started playing out only the left side of headphones or speakers. I know it's not the headphones cause I've tried it on other devices and no matter what is plugged in to it, on only comes out left side. From the forums I've read it doesn't seem to be a sound card or the logic board, otherwise it wouldn't be working at all. The most logical explanation is that the connection inside the jack is messed up, but the mac is only 1 month old. I've checked the setup on sound preferences and Audio MIDI Setup and both seem fine. Does anyone know how to fix this without taking it to warranty service? Thanks.