Mezmo, I've had this specific problem just as you described with the left channel of my Bryston 3bst. I wonder whether there may be a design flaw in the Bryston gear? I contacted Bryston, and they advised me that I likely had a 'mute' problem (whatever that is - sorry, I'm no engineer) and that I could return it to get it fixed. However, last month, I had a party at the house so I moved my system to the living room to entertain. Upon returning the system to my bedroom I find that I no longer have any trouble at all - perhaps it was just a lose connection or something. Anyway, I suggest you return it to Bryston - their service is great, and of course free. Good luck.