Good morning and welcome to fixya. not a bad setup you have here at all, you ned to start by checking the speaker wires inside the box to the connector inside and then the wires from connector to amp on outside. if everything looks fine there, then you need to check the amp for power out of the rca plugs to make sure the channel is not dead. if you are looking for a new amp you can try several different ones from fosgates new line up to soundstream's. im running 4 polk momo 12's on the tarantula amp and love it. they are great amps. hifonics also has a new line up pretty cool stuff, heard really good things about there stuff to. good luck and let me know so i can help you out.