I have been using an iPod, with a belkin adaptor pluged into the 12v outlet. It comes with a dock type plug that plugs into the bottom of the ipod. You then plug a male/ male mini plug cable between the Belkin and the the aux input in the TCH. (rather than the ipod and the aux input) Another feature, is this allows the ipod to pause, when the car is turned off, charges the ipod battery, and provides a volume control on the Belkin, that allows you to set the volume so that it is the same level for aux, cd, fm etc.

I notice no difference between sound quality this way between ipod, or mp3CDs, which I also have loaded in the changer.

I leave the ipod in the closed compartment, safe and hidden.