Try using a really good set of mains. Crimson is making ultra high quality for there
Crimson preamps and Power amps and as you can see by the photo they use 2 huge
toroidal transformers in each mono block and with there solid core mains and hospital grade plugs there’s absolutely no hum. This will make a huge difference
in the sound and should stop the hum. Now I-know the US importer as they you only get them with there products. But the US importer will help folks get ultra quality mains hers his email
[email protected] give him a try plus
he’s extremely reasonable.