Rockford 1 farad capacitor

The 1 farad capacitor is something added to current hungry systems to help keep the supply voltage at the proper operating level.
If your amp does not work after putting one in your system, but it worked before you put it in, you most likely have it installed wrong.
The capacitor should be put in parallel with the main +B voltage of the amplifier. That means you would connect the positive side of the capacitor to the +B voltage supply of the amplifier and the negative side of the capacitor would go to the chassis ground.

If you have it connected in series, or inline with the +B voltage supply, the capacitor would be blocking the voltage to the amplifier.

Without more information on your problem that is the best answer I can give you.
If this does not help, please supply more information and I will be happy to help you further.