I'm no expert, at anything in this field but consider myself an avid hobbyist with some experience. In general, high current sources like A/C power supplies, even the cords used to convey the A/C generate electromagnetic fields. For instance, if looped, form the basis for the magnetic field that drives the armature of an electric motor. Because of these electromagnetic effects together with other types of electromagnetic interference, (some still not clearly understood), it has long been considered a good idea to separate the power cords from the low level or even line level signal cords. These include the 'interconnects' that convey the signal from any of your sources, like a DVD player, to your pre/pro or receiver, as well as your line level or speaker cables.
Actually, this topic of interest is huge and many references can be found in many of these forums. It has been my experience that it is best to separate the A/C from everything else by at least several inches, more is better. Cords may cross at right angles without problems. I hope this helps.