Buzzing through speakers

Hi,
I have a Denon X4700h for home theater.
While i have bought the uniti star i linked them together from front pre-out on the AVC to the Analog Input 1 (rca) to the Naim.
When I switch the naim input to Analog1 there is a buzzing noise very disturbing.
The noise still there even if i turn off the AVC.
I have tried switching the earth to floating this sometimes stops it but not every time
I am using the pre out of my star sent to my Cyrus power amps
Can some advise a solution
Thanks for your help