Thanks much, Monophoto, for your assessment of the situation. Yes, the head is an original. What we don't know yet is if the power company will remedy the situation, which, as it seems, is fairly widespread where we are, in a "rural" area. Apparently, if they boost the voltage for us, then this may create problems of over-voltage for houses closer to the transformer, or at least this is what they have told other users with similar problems.
Another suggestion I received was buying an adjustable transformer that could be adjusted to the real voltage entering the transformer (to compensate for the fact that we are getting 184 instead of 220). Personally I have never seen one of these. What remains to be seen is if this voltage remains constant throughout the day. My friend suggested that at night when there is little consumption this might change, but I do recall using the enlarger at night with the same problem.
So most probably we will have to get a radio for the darkroom to drown out the hum. Times like this make me recall the spartan wisdom of E. Weston and those of like habits.