The aftermarket amp I have has RCA inputs ... i assume these would be used to plug in the head unit on an aftermarket set up.

does anyone know what would happen if i took an RCA cable with a headphone jack end for my iPod and plugged it in??

would i get muffled sound only out of my sub? or make the car self destruct?

 

Would work fine assuming your amp has the proper x over setup. I do it all the time to bench test used amps before doing instals. Sucks to spend hours wiring up a system only to find out the amp is blown.