Poor, crackling sound output from both output ports. Why?

My ipod touch 4th generation has been acting strange recently, there is sound output from the headphone jack, however all of the low-end sound crackles. This is a recent issue, and at first I thought it was my headphones, however I played all of the songs that crackled through the same pair of headphones from a laptop, and there were no crackles. I have tried different headphones, even running the sound through a stereo and a bass amp (which is obviously meant for low end and never crackles) and they all crackled, but only when the sound was coming from the ipod. It also crackled when I plugged it into an ipod dock. I listen to a lot of dubstep type music, especially Deadmau5, and also make a bit of my own, and my headphones only crackle when they are plugged into the ipod, is the jack just faulty, or is it something deeper in the ipod? Again, this is a recent problem, Thank you.