I have 13" MacBook Pro (Late 2009) model that is refusing to play sound on the right audio-channel.
Without any speakers connected it still plays fine but once I connect earbuds or a headphone, I only have sound in my left ear. In my right ear I hear a very low white noise sound.
I've tried rebooting, fixing disk permissions (very long shot, I know), same problem if I play sound in a virtual windows machine. And off course I've verified that the sound balance is set to both left and right.
I've "looked" into the mini-jack output but can't see anything wrong with it...