Interesting topic. I have a Blue Circle MR1200 balanced power line conditioner/distributor and it too has a tendency to buzz/hum audibly. The noise appears at intervals of between 15 to 30 minutes, it starts out low and increases in volume over about 30 to 60 seconds then subsides into silence. I have been told by Blue Circle that the AC from the wall must be particularly dirty and/or it may be due to the on/off cycling of the furnace. They say the noise is indicative of the balanced transformer working hard to clean up the AC.
Are there any devices currently on the market to clean up DC offset, if this is what I'm experiencing in my home? The company that makes the Ah! NoeToeb 4000 CD player also sells a device called an AC Offset Killer, and I wonder if its just misnamed. Any thoughts?
