A mate of mine at work has just bought a T742 (on my recommendation) as a bolt on to his existing 2 channel Audiolab (+Naim) system. Everything works fine except there is a hum through both the centre and the rear speakers. The front l/r speakers take a pre-out feed from the NAD and go through his Audiolabs for their power and there is no hum at all on these so it sounds as though it is the power amp section of the T742 that is introducing the hum. Any ideas or similar experiences? Matt.