It sounds like you have a loose nuetral in the electrical panel or behind one of the receptacles. If so then it should be checked immediatly. If an electronic device looses a nuetral completely then it will smoke every electronic circuit board that is plugged into that circuit. I know from experience ive done it myself. try an extension cord to your surround sound and tv just temporarily and plug the other end into another part of the house then see if you still have the same problem. If not then that would rule out that there is a problem with the electronics.