^Yeah, I'll try to explain to my understanding, since Sean doesn't go into detail unless asked. Certainly see capacitors used on positive wire in between amplifier/headunit to speaker terminal, but in this case your using a very large capacitor for a different intended application. Using a capacitor inline to an amplifier to help stabilize / stiffen the electrical supply is almost always bad. They don't store enough power to actually help, certainly don't keep up with the amps power draw, and since they don't store enough power they are constantly discharging and recharging, thus sucking more amperage from your battery / alt. Just adding another item that draws power. Adding a battery is a better idea, even if its small. Make sure its a sealed agm type, otherwise it'll leak poisonous gases in the cabin. Hope this makes sense, typing on a mobile is a trick sometimes