question about amp

2 days ago my amp went out it says low voltage so i checked my battery its fine but im not sure what it is i thought it might have been the amp so i took it back and exchanged it it still says it so what could it be i checked all connections and there fine any ideas

check your ground...
if you have a Volt meter...test @ the Battery....before and after the inline fuse....and then test @ the amp...

my ground was frayed i couldnt tell cause of the peice that was over the connecter