When im watching Sky Sports HD im getting this sound issue i cant sort out ! iv tryed changing all the sounds that the amp can do and it makes no Difference. It doesnt do it on any other HD Channel , just the Sky Sports HD , The sound sounds like when you have a old CRT TV on a channel with no picture , You know the one thats on the Film poltergist , Its a really high pitch sound and its driven me nuts , Any ideas on whats doing this and how i can stop it ?