Hi George/Steve

When I tested the rear 5Ks I just changed the lead at the 565 end and plugged them into the digital front out. That qualified the digital cables working. I did check the balance control L+R in either direction. I have tried 2 x other digital cables from the 565 to the 5Ks while leaving the coms on the existing (buried) cables with no joy.

As suggested by Steve I have re-typed both the 5Ks as the opposite to what they are (LR Surround slave to RR Surround slave and the noise has gone. When I put them back to normal and re-typed, the horrible distorted static noise was back.
Changed them back to the wrong way around and all good again with no noise.

Really confused now. Might swap the two speakers over manually tomorrow to see what results this brings. The mystery continues.

Thanks all for your help so far.

Andy

500, 518, 565Z3, 5500, 5000HC, 5000 and 2 analog REL subs.