Just bought a Sony xbr 75x850e and tried to hook it up to my amp that runs 3 external speakers , using same method that worked with my 2008 Bravia kdl model, but no sound. I think the problem is that I was attaching the red and white plugs to the back of the tv in a spot that is audio in? But there is no red and white audio out. Obviously I’m no audiophile. Any assistance would be great.