A couple of weeks ago I woke up to find my desktop computer external speakers spitting out a loud and horrible hum. Nothing was playing though the speakers at the time; in fact, the computer was not even turned on. WTF, I thought.
A few other observations that might aid in a diagnosis of this problem…
I switched out another set of speakers. They work fine, so I know that the PC itself is not generating the hum.
The manual volume control on the speaker box had no effect in reducing the hum, but if I turned the control all the way to OFF, the sound stopped.
As is customary, the 2 speakers were connected to each other by a wire. When I disconnected that wire, the one still-connected speaker continued to hum.
These speakers are self-powered; that is, there is a line wire that comes from them that must be plugged into the wall. If they are not plugged in, they do not hum (or funtion at all). FYI, this particular pair has one of those transformer blocks at the plug end.
Does anyone have any idea what is going on here, and if it can be fixed? I have a suspicion that this is not a unique problem.
Thanks all, in advance.