whats broken?

[Comet]

i recently got an mp3 player which i do not know is broken or not. When i put my earphones in its all quiet and all i can hear is the instrumentals of the song and a bit of lyrics. but when i twist the plug when its inside the socket it becomes clear again, for a few seconds. is that the earphones or something wrong with the mp3 itself?

[Shoeberto]

Sounds like a problem with your headphones, though it could be a problem with the headphone port on the player. Try with a different headset to see if you get the same thing.

[Hawkeye]

What mp3 player, also?

[Comet]

i dont know because i bought it off my friend (it worked fine for 1 week) but at the back it says a code 505SDMPS