glad to have helped. That center pin is a current supply line a bit like the one tied on the usb ports, to inform the device how much current it is allowed to draw from the device. Devices that believe the source can't supply enough current will refuse to use the power source, as a safety.
that's where the "you can't charge this ipod from that usb port" message comes from. works the same on this adapter. the old white bricks for the older minis don't supply enough power to run the newer white minis for example. That large cinema brick appears to rule the roost for current supply however.
Since current is supplied on demand, there's no danger in attaching a bigger current source to a smaller device, you won't "blow it up".
