Hello forum, once again having found you after many unsuccessful searches on yahoo - google came up trumps!. Here's the thing.... I've had a PSW2000 for some time, it has served me very well for my modest needs. After i moved house (probably coincidental), it has started to emit an annoying whistling at a low enough level not to be an issue during loud scenes, but bl@@dy infuriating when things get quiet. It's not a constant sound, but it kind of whistles and chirps way above the amps' normal output frequency range. I had another amp sent over from KEF which had exactly the same problem. So I sold one on ebay and the buyer said it was fine????. I have tried the sub plugged into different main circuits around the house and it's still doing it. Is it possible this noise is coming in from 'outside'? Oh, one more thing; when it's hooked up to the dspA1 amplifier, all the speakers start making the same noise as well. Any guidance would be greatly appreciated.