I'm looking for some help hooking up my amp. I will not be using RCA cables because of my stock head unit. I'm thinking I can just get the signal from the stock speakers. Not sure exactly how it would work. I'm assuming the speakers in the back of my car will have the right signal. I also am thinking I will use a toggle switch to turn my amp on and off. So my question is how can I get the signal from the stock speakers to my amp so my amp can tell my new subs what to do.