I just bought and installed a JVC KD-G800 head unit in my 93 Explorer.It has a sub out connection on the back so you can control the sub from the head unit but the output is only rated at 2.0 volts,but the line out connections are rated at 4.0 volts wich would be better to connect my JBL GTO601.1 mono amp to?
the voltage level on preamp outputs are just for signal stregth, use the one thats designated for your subs. that output most likely will give a crossover plus that output is non fading, so when you adjust your treble and bass from the head unit it wont mess with the performance of your sub.