I turned on my amp this morning and there's a loud, quite deep, buzzing sound coming from my front speakers. The sound doesn't seem to affect the centre and rear speakers. I've checked the connections and all seem ok, but whilst round the back of the amp I did notice that the 'digital out' socket was flashing red (I have nothing connected to this socket). I fiddled around with it and nothing seemed to put it right. Anyway, just by chance I turned on my DVD player, which I have connected to the amp by a digital-coax cable, and the buzzing sound stopped. The flashing red socket also stopped flashing and stayed a constant red. As soon as I turned the player off again, the flashing and buzzing started again. The amp is a Sony 1080. Anyone any ideas as to what has caused this to start happening? Or better still, how to stop it from happening.