Arcam setup buzz problem

[Roost]

One of my friends sent this to Arcam themselves but i thought whilst waiting for a response i'd ask on here see if anyone has an idea what it maybe?

"My setup is as follows

Arcam Alpha 10 Amplifier
Arcam Xeta 2 Home Cinema Processor
Arcam Alpha 9 CD Player
Arcam Alpha 8 Tuner

The problem i have got is an audible buzz eminating from the Alpha 10 amp.The buzz can be heard either through my speakers or when i connect my headphones even when only the amplifier is switched on. I think my next step would be to remove the amplifier and test it in another house?"

Any advice that i could pass onto him would be appreciated