Just a quick question.

I am helping a budyy out with an install. He wants to run a 4 channel amp for his speakers and a dedicated sub amp. My problem is the deck he got only has the 2 preouts for front and rear. So what is my best angle to tackle this?
Do I run into one amp and then use the output on the amp to run to the second amp or is there some other way to wire it?

I have the same setup in my own car but I actually have the 3rd preout for a 3rd set of rcas....I've never encountered this problem before.

 

get a different deck with dedicated sub preout? lol but seriously you can do a single rca input into the 4 channel with success you just wont have front to rear fade. if it doesnt have the input selection for that just use some decent rca y adapters into the 4 channel using the front deck rca output and voila. 4 speakers that work and sub in the rear.