I have never had an issue with my 7500 being powered from the APC H-15 which supplies about 15 amps of current or 1800 watts. Same goes for my 7125 which is also in a HT setup with a big Samsung DLP. By not protecting the amp from a system ground fault, say due to lightning, you are really leaving it open to damage. It could also go back through equipment connected to the amp through the ground and cause damage. Although the XPA-2 is rated at 500 watts into 4 ohms, it is only 2 channels and does not draw any more power than the Outlaw amps at full rating. I sleep a lot better at night and during a lightning storm knowing the APC is on guard.