I have one of those defect Macbooks with the extremely sensitive headphone jacks... I've had it for 2 years, so I'm sure any hope of having Apple replace it is gone. What can I do to fix this? I'm a musician, and I need to have a reliable way to have audio input and audio output into a speaker without having to worry about bumping the cable in the jack. Is there any reliable and high quality USB headphone jack out there? Thanks!