I realize you are looking for a solution without a "head unit", but I'll show ya what I use.
I've got one of these:
...it's a DLO TransPod and it charges the iPod and provides a line-out connection to your stereo. The version I have also broadcasts your music on a FM station of your choice (Kinda cool at the lake--all the radios in the campground can tune into it).
I built a little bracket for it that swings out of the way. Originally, it stuck in the cigarette lighter socket--I just wired it to the ignition switch instead. The line out connection is much cleaner than the signal from the headphone (or the FM signal).
I'm have a guy making a small adaptor box to go frm a Creative Labs MUVO to a power amp... Supposed to be only a few things in the unit... this way it fits into the ash tray and has FM stereo..
Just get one of the little RCA plug to headphone jack adapters and jack straight into the amp. The power output on an Ipod is in the milliwatt range. Remember it is not trying to drive a pair of 6x9's. The voice coil in a pair of headphones is VERY small. Don't believe me? Try hooking your Ipod straight to a PAIR of 6x9's and see how well you can drive them. Why do you think all of the docking stations have their own amplifier?
As an added bonus, the Ipod sounds a hell of a lot clearer without being filtered by the stereo and no one can jack your sh*t when your car is unattended if you take your Ipod with you.
I am running a Kenwood 4 channel in a bridged configuration with the Ipod jacked straight into the RCA jacks. No stereo, no problems!
I called Kenwood this morning and talked to a tech guy for 10 minutes or so about this. Although it was evident he was trained to push product, he at least admitted that Kenwood had no info on this since no one had "officially" tried it. I have talked with my stereo guru in town and even he couldn't understand why anyone would want ONLY an Ipod and no head unit but he at least agreed with the logic of how it would work.
If you have ever taken apart a pair of headphones and looked at the wire size on the voice coil you will know that there is no way any handheld mp3 player could overdrive your amp. Those wires are thinner than a human hair and would smoke in a millisec if subjected to the kind of power it would take to harm an amp. Kenwwood said the typical wattage at the preamp outputs on the back of most of their head units is in the 1 to 5 watt range, way above that of any handheld device.
I run a Harmon Kardon GO+PLAY docking station at the house and it 2x30w tweeters and 2x30w woofers and it absolutely kicks ASS so it doesn't take much for an Ipod to sound good.
Thanks for posting all the answers. You are a stars
I had the same problem and now I can listing and singing my tunes. My favourite tune at the moment is M.C. Hammer parody. Its funny video to this song. You can check it out at http://www.pennysaverusa.com/savertime/ lol
What about your tunes? What are you lising while draving?
I did it. I got an old Sony amp off bay for $10 shipped, hooked up a couple of 3 way 6x9s in the rear and use a 1/4 to RCA adapter cable I stole from my gig bag. I run my iPhone through it, set on random repeat and stash the iPhone in the ashtray. I figure I don't have mush invested and only use it about 30 minutes a day or so. Been doing it this way for two months with no issues.
not sure how it really went down but i did what u r proposing about three yr ago.......works great. if u have the fancier ipod it has an equalizer built in so that you can tune the sound as you please. you can buy an adapter setup that will go straight from the ipod to an rca cable for the amp. i used the plastic case that the ipod came in as an mount and just mounted it on the dash. since its clear plastic i got a lil fancy and put a blue led behind it slightly thru it so it would light up the outer edges of it.....pretty snazy......
Bringing an old thread from the dead. One thing you could do is get a pre-amplifier or equalizer with an AUX input. I am going to run a Power Acoustik 7-Band Graphic Equalizer to a MB Quart 2-channel with 2x100 watt RMS to feed a set of MB Quart 6.5" Component set installed in Fiberglass Kick Panels. Should be able to dish out some quality tunes. Welp...