I bought a set of speakers for my MBP today (Logitech X 240 3.1) And Ive noticed that when the power adapter is plugged into the computer, a 60Hz hum comes from the speakers. Playing music covers this hum up pretty well though. The second I unplug the power cord the hum goes away. I have tried different combinations of hooking one up a power strip and the other directly to a wall outlet thinking that might help. Its nothing catastrophic, but has anyone else had a similar problem? If so what have you done to remedy the situation?