I recently discovered a hum in my system that I did not have before. I thought that I would disconnect everything except the optical cables and start from scratch. The hum is definitly coming from my Monster line conditioners. The 3500 and 3600 model. I have had a number of power surges over the last year. Three or four to be exact and I was always happy to see that there was no damage to my system. However this hum is a real pain in the a.. even though I do not hear it from where I am setting.

Will this hum cause damage to my speakers? Is it possible that there is damage to the line conditioner from the power surges?

My left main speaker is about a foot away from the line conditioners and two feet from the processor. The right main is two feet from the amp and four feet from the processor.
I have B&W 804 speakers.

While I do not think that this is a serious problem I would like to solve it.
The outlets in this dedicated room are fairly new and grounded. I do not think it is a electrical problem giving that the problem did not exists before. I do have one extension cord for the projector running though a pvc line with the ground cable that is attached to a cold water pipe. Also I have an antenna line runnining thought the same piece of pvc. The other component cables are running though a seperate pipe of pvc.

Is there an inexpensive meter I could purchase to check things out as I go along?

Any suggestions are welcome.. Thanks in advance and MERRY CHRISTMAS to all!