I'm sorry there is a thread on this i couldn't find it but my bass is kinda broken. Firstly i plug it in and it play good and then it slowly dies. no matter how high i turn it up or how hard i pluck all i get it s muted sound that is not very good. i have tried everything from trying different cords to different amps and took it into my local music store. all they said that it has a bad connection but did nothing about it. it would be very nice not to have to buy a new bass.
Raise Your Hand If you Like:

3 inches of blood
Amon Amarth
Coheed and Cambria
Death Cab For Cutie
Every Time I Die
I Killed the Prom Queen
In Flames
Pride Tiger

My cousins band from Vancouver-NWOBCHM- myspace.com/scarstruckmetalband
bring it to a store where they repair instruments. They should be able to diagnose the problem. To me it sounds like you have active electronics, and the battery is dead. Not sure tho. good luck