i just got a set of stereo speakers for the mac book pro, but they have a very annoying hum. im told this is most likely caused by being plugged into the surge protector. i can check this when i get home, but if i find that they hum because of the surge protector, and that i have to plug them into a different socket, is it possible that a surge could come up through the speakers and into the mac book pro via the headphone jack ( audio out) on the MBP?