Putting an old rockford fosgate amp in girlfriends car. She's got a 10" sub currently running off the head unit. Two questions:
1. The amp has three power leads: "gnd' "ap" and B+". I'm assuming gnd is ground. Between ap and b+, which goes directly to power, and which goes to pwr antennae lead on HU to power it on?

2. Since the RF amp is old school, it's only got leads for lt and rt speakers. Since I'm running to only one sub speaker, do I mix lt+ and rt-? vice versa? Or just run off one side i.e. lt+ and lt- and leave the other side disconnected?

Thanks!

 

ap is Accessory Power. Connect that to any switched 12v source. Many HU's have a lead for accessory power, or you can tap into the switched 12V that powrs the HU itself. If you have never wired an amp before be sur that you are using the appropriate size wire for the constant 12v+ directly from the battery. Also be sure you fuse it correctly.

As far as hooking up the sub...well it depends on the amp. If it is bridgable (many older ones were not IIRC), then yes just hook up lt+ and rt-. As far as I know you can also do it vise versa.

 

If it is a dual voice coil sub, then connect the rt+ & rt- to one connection and lt+ & lt- to the other connection.

If it is a single voice coil sub AND the amp is bridgable, then bridge the amp and run the wires rt+ for positive connection and lt- for negative connection.

If it is a single voice coil sub AND the amp is NOT bridgable, then just run rt+ for positive and rt- for negative.

grd = ground for negative wire.
B+ = positive battery connection
ap = remote turn on lead (if you use power antenea power, it will not turn on when you use the CD player or aux input for MP3 or IPOD)