you have a ground loop problem. first check if the amp is still on when the radio is off. you probably don't notice the ground loop when the radio is on is b/c its being drowned out. i'm guessing you have a stock head unit and they wired it to the acc wire instead of your pwr ant wire. i can't remember if there's a pwr ant wire on the rsx's if you do than wire your remote wire to it or put a switch inline with the remote wire so you can manually turn it on and off.