Had Sky HD fitted last weekend, Since then I haven't been able to watch anything in DD5.1 as the signal keeps 'dropping out' & back in again every 2/3 seconds. This only happens on the HD channels. I can watch SD channels via optical without any dropout of signal. I have the box connected to my Denon 1602 amp via Optical. I have tried changing leads without success. 1) Is it my amp (compatability issues) ? 2) Is it Sky (signal) ? 3) Is it my Box ? Any advice help would be greatly appreciated.