Interference on your audio/video? Check this.

[Ashen]

http://www.rane.com/note110.html

Pretty informative. Helped me get rid of my interference issues. Applies to interference on video lines as well.

 

[ShockSlayer]

tl;dr

I'm guessing the basic principal is to connect all ground and use shielded cables? That's whats always worked for me.

SS