hi. recently set my n-vi up and all is quiet for the first few minutes, but sooner or later then fan kicks speeds up and it, together with a loud tick / clicking noise can be heard across the room and over quiet music or dialogue.

how much noise is normal?? thanks all.

There should not be a ticking sound.
The fan should only come on when very warm.
Do you have enough space around and at the back of the n/vi?

Even when the fan's running on mine it isn't audible... can only hear the fan by being behind it, certainly not from my listening position 8 feet away from the n-Vi.

What firmware are you running?

http://forums.naim-audio.com/eve/forums/a/tpc/f/3452929996/m/3592918807

see above link on how to get firmware revision