What are preamp outputs on car stereo?
Preamp Outputs: Preamp level outputs are audio outputs that are used to drive an amplifier (or equalizer or crossover). Preamp level outputs do not have enough output current to allow them to drive speakers directly. They are generally included on higher end equipment.
How many speakers can you run off a head unit?
While the vast majority of head units will be able to power just 4 speakers, but some can power more and some, less, so in order for us to give you an answer to this question, we would need to know the model of head unit and the car that you are wanting to install it in.
What is RCA voltage?
A good quality RCA audio source should have a voltage rating around 1-2 Volts and a low impedance. The voltage is the “strength” of the signal and the “impedance” relates to signal integrity once the RCA is plugged into the amplifier.