Maybe we need to list what a surge protector can and cannot do.
Can do: Stop errant voltages from utilities mis-wiring. Some surge protectors (Tripp-Lite) can isolate outlets from each other, thereby isolating power supplies of commonly connected components like amp, preamp, cd player, tuner and so on.
Can't do: Stop a lightning strike. Stop a surge from a nearby device (furnace, refrigerator, freezer, AC, sump pump). Filter out line hash or DC offset. Prevent a ground fault, or suppress an errant wiring condition.
Wayner