What power conditioner will help in my situation?

Yes, I agree that trying a long extension cord running to a different room should be the first thing that you should do, at least as an experiment.

But can you clarify what you mean when you say "when I change the fan speed there is a low frequency hum when I turn the fan speed from low to medium etc." Does that mean that the hum occurs only while you are changing the fan speed, and perhaps for a second or so afterwards? Or does it mean that the hum is always present, but is affected in some manner by a change of fan speed? Or does it mean that the hum is not present in "low," but is present at the faster settings?

Regards,
-- Al

PSAUDIO P10 works well for me with the same problem

I'm glad I have user adjustable electronic switch board with more dosens of combos how to customize outlets and power.

How about a regenerator?

Have a qualified electrician run a dedicated line or two. It really doesn't cost that much to do so. They really do know what they are doing and how to do it. worst case, run on wall wiring in on wall conduit from another circuit (preferrably one not used frequently) to your listening room.

enjoy