Click here for one possible explanation, but the "one minute" thing sounds like it could be more complicated than that.

Sounds like something is miswired, causing the ignition-switched wire on the player to maintain voltage after the car is shut off. For instance, if you connected it to something other than the ignition-swiched wire on the car. An example would be if you connected the Orange wire from the sled to the Orange wire on the car just because they were the same color (assuming that the color codes meant something without actually checking what each wire did). On many aftermarket harness adapters, the Orange wire is actually the headlight sense wire, not the ignition switched wire.