Hook the mp3 up directly to the sub?

Also I am starting to think its the sub, a friend and i were playing ps3 and all of a sudden it turned on,the first time ive heard and felt it, so i took the cover off to see if it was true and then it shut off almost immediately. The test tone worked when i first hooked the sub up but seemed hardly noticeable,now i cant get any signal through it what so ever.