I get an annoying background buzz with my Oppo 980H. The power is filtered and the sound is carried by the supplied HDMI cable which according to most forums is high quality.
It is coming from the speakers. The DVD is connected to an Onkyo 606 with Q Accoustics 5.1 setup. I also have Sky HD and a Panasonic Bluray piped up the same way but they don't buzz in the same way. The Oppo has a huge array of settings and i wondered if I'd got something wrong.