Sound louder in right Ear!
If its not something simple like a balance control in your player or a bad earbud (try a different set of earbuds w/a 3.5mm jack).
Then try this:
Theres no mention of a balance function in my Itech manual. It could be a loose solder connection on the board. Thats a common thing to happen with and circuit board mounted hardware that goes out of the unit. I.e. to your ears. Ever so slightly move the earbud jack back and forth, up and down and see if you hear static or the volumes change. If so theres 2 things to try....
First try some contact cleaner, spray it on the male jack and plug it in and out of the unit a few times for a simple try at it.
If it still has imbalance then take the cover off, for the jack side of the unit, resolder the little pins of the inside jack to the board (on the backside of the board). Or find someone that can. These units are worth a few bucks to repair IMO.
Hope this Helps