I upgraded my Mini 9 from Leopard 10.5.7 to Snow Leopard 10.6 today. I use my Mini mainly for listening to Spotify (music app) through my headphones. I've never had a problem with Leopard, but now I've upgraded, I can hear static 'white noise' through the speaker (but only when I have headphones in). Playing audio through the speakers seems fine, and when the volume is muted there is no static (the louder the volume = the louder the static).
Does anyone have any suggestions? I've tried some general audio fixes and they've not done anything for this problem. It was all working perfectly under Leopard!