Audio only in one channel

Currently my iPod 5th generation iPod from 2006 is only playing audio through the left channel, when having head phones attached. I've tried different headphones, which all work fine on another iPod and MBP, and they all showed the same problem so it has to be the iPod.

If I pull out the head phones about 3 milimeters, I get audio in both channels, but at a distorted, lower quality? I thus thought it was the head phone jack, and bought a new one including connectors, and replaced the old one. Unfortunately, this didn't fix my problem, and I am now at a loss at to what the problem can be? Any ideas, suggestions, or experiences?

Would be sad if it has to die, since the battery is still giving me 10 hours on a full charge after 5 years of heavy use.. 😟