I've seen a couple posts about which wires are to which color, but i was curious if there was a simple way to hook up a radio to a power supply. I know there a few different models between the years of the FC, and I got the S4 one (picture included).

 

If you are wanting to bench test it, check out a reverse wiring harness like this one
Metra Part # 71-1781 | Mazda wire harness | Metra Online

I'm trying to get a bench setup for my S5 radio, because alligator clips just aren't cutting it. Different plugs, but same idea.