I have the 875 and have no problems. There is a adjustment on the 875 and 805. To get a good adjustment try having the sound coming though the TV and the amp at the same time then adjust the delay until you have no echo.
There is a lot of issues with this on all the receivers, just do a google search.
I do understand your frustration though, I had a new Yamaha receiver that would crackle and pop after about 45 minutes of play. Ended up taking it back and buying a Denon. The Yamaha was the better deal at the time, but I just couldn't get over the problem.