It might have some effect, though this is not a true
isolation transformer
This would be the more
likely candidate, let me know if you get it and how well it works. I'm in the
market as well due to the crappy old wiring in our house. It also occurred to
me that it could very well be caused by wireless interference or perhaps a
neighbor operating a ham radio or heavy machinery like an arc welder or
big electric saw. Do you have any big power lines or microwave towers
near by?
When I was recording at
the Technical Institute Studio in Istanbul with Erdem, They had an isolation
transformer the size of an industrial refrigerator, and we still had some
radio interference. Is it possible you have right wing extremists operating a
pirate radio station near by? hey it doesn't hurt to ask:-)
Bill