I want to order a small 100 watt amp and needed to know if it can get powered by the head unit by connecting it with the rca cables.. thanks..
The wattage of the amplifier makes no difference. A new amp will have a specification for the input sensitivity. This is how many volts from the source will drive it. The line level output from your head and line level inputs on the amp should work. Line level outputs will probably not drive speaker level inputs on an amp very well.
The RCA cables do not supply power to the amplifier; they just carry the audio signal from the head unit to the amp. Your amplifier, regardless of its power rating, will need power and ground connections in addition to the RCA and remote outputs from the head unit.
