AC Filter necessary?

Am I doing my system a great disservice by plugging the amp and preamp directly into the wall outlet? Can they be damaged by power surges and the like? Can anyone recommend a an ac filter or something to protect my amp from damage and improve sound? Thanks for the help.
What are you using for power cords now? What is the current draw of the AMP(s) at max. output [should be given in the spec sheet]?
I was told by a respectable power company that Amp and Sub are able to protect themselves. They recommended to plug the Amp directly into the wall. This will allow the Amp to draw more current. My Amp is plugged into the wall for the last 6 months and without any problems.

The NAd amps have a built in power cord, non replacable. I'm using a 50w per channel amp. Have you had power surges while your amp was playing Rodney01? It just worries me that I could dmg hundreds of dollar worth of equipment due to a power company error, etc.
Buy a Tice unit.. BIG improvement in sound.. I would not plug anything into the wall after hearing the Tice improvements.