sound from left earbud

So I had been using a pair of skullcandy earbuds to work out and noticed the left side was loud and sounded terrible, like it was distorted, and the right side was barely making any noise. I then turned the volume all the way up and both earbuds sound fine. Left isn't distorted at around 90% volume (which is pretty loud) and the right side is just as loud. Anything less than that and the left side is distorted and the right side is about half as loud.

I figured it was the buds themselves so I went and purchased another pair to see the same thing happening.

Just to be safe I hooked them up to my wife's iPhone and they work like they should.

I've checked the accessibility options to make sure I don't have my balance messed up, and restarted my phone countless times to no luck.

I also went through my cydia tweaks to make sure nothing stood out, and haven't found anything there either.

This is an iPhone 4 running jailbroken iOS 6.0.1

So, I took my phone to an iPhone repair shop, they replaced the headphone jack. That didn't do anything at all so I got home and upgraded my software to iOS6.1 and still having the same issue. I guess it's an issue on the motherboard itself somehow. It's the only explanation I have left since I've replaced the headphone jack, tried multiple headsets, and have now upgraded my operating system and still have the same issue.. Guess I'll be heading to AT&T today to get a new phone. Fortunately I'm eligible for an upgrade.

Thanks for the help.