Have you considered an isolation transformer? Plitron makes a good one, and they sell to the general public.
Thing with isolation transformers is that they hum when they are working hard, and other times too, so it's essential to position them outside the listening area, like in a utility room.
Thing with isolation transformers is that they hum when they are working hard, and other times too, so it's essential to position them outside the listening area, like in a utility room.