Photo of the phono sockets for the cable to HiFi amplifier.
OK, we need some sound out of this thing somehow.
The iPod thinks it is connected to an external device via a docking station. Therefore it sends its audio out the "line-out" pins NOT the iPod headphone socket.
The line-out audio is wired up to two phono sockets shown here. A suitable cable with two phono plugs on each end is then used to connect it to a HiFi amplifier if that is what you want to do.
You can connect the line out wires to a headphone socket, and indeed I have run them from these line-out phono sockets to a headphone socket, but it is very loud, hence the presence of the two 10K Ohm potentiometers to adjust each side of the headphone volume.