white noise from tweeters

I recently purchased a Naim CD5i CD player, Naim Supernait amplifier and B&W 805S speakers. Using Cardass Crosslink for speaker wire.
I have an almost inaudible, I have to be within 12", white noise coming from the tweeters. This doesn't affect the great sound coming from the system but it does annoy me.
The noise remains after disconnecting the CD player and it is not affected by increasing the volume. I'm certain this noise is generated by the amplifier and I'm curious if anybody else has experienced the same thing.