I think many people have this problem. I think it is well known. Like you say, when the 950 first turns on, everything is silent. When an analog input is selected, there is hiss and it does NOT go away. When a digital input is selected, the hiss stays. See this thread for more info: http://ubb.outlawaudio.com/ubb/Forum15/HTML/000513.html and also to see how the hiss may relate to the signal to noise spec.