[Tenrocca]

Merv - I think think your still going to need some sort of pre-amp before a power amp, if nothing else to adjust the volume. It may work OK by just plugging the iphone in and adjusting volume through the phone, but probably not an ideal setup. You might have an issue with turning the amp on and off as well - power amps would usually have a "turn on" signal from the head unit.

Cheers