I have a 6.1 Surround SOund system powered by a Yamaha RX A750 home theater receiver. I want to boost dialogue for myself using "TV Ears" made by Sennheiser (Set 840-TV headphones,) while others continue to enjoy the Surround Sound. The headphones jack cuts off all sound to the surround sound speakers. And if I route audio solely through the TV, of course, that too cuts off all sound to the surround sound speakers. If I route the audio to both the TV and the amp, there is a very noticeable echo effect caused by one lagging behind the other. But I can't seem to get audio out of the receiver to the Sennheiser unit. The Yamaha has many RCA jacks, and I have the splitter/adapter wire, but none of them seems to output to the Sennheiser. Can anyone help?