Ipod Audio Balance Silver Ipod Classic 80G

I jus got my new Ipod installed Itunes and loaded with music.. When I plugged the headphones, SURPRISE!!! MY IPOD SOUNDS MONO!!!! THE SOUND COMES OUT JUST FOR ONE EAR.. I TRIED DIFFERENT SETS OF HEADPHONES BUT IT'S THE SAME WITH ALL OF THEM... I re-installed the Itunes and restored my Ipod, but the problem persists.

I checked on the Ipod's menu and it hasn't balance options!!! Does this means that my Ipod is defective??

Has this happened to anybody????