I'm new to the community and I'm not sure this is the place to be asking, but it seemed reasonable to give it a shot. Also I'm not an electrical engineer so I'm not familiar with the English jargon.
I have a Marshall guitar amp which operates at 127V BUT my house's electric wiring is monofasic, ungrounded, operating at ~220V (ranging from 207 to 230 according to a neighbor) so I have to use a tension converter.
The problem I'm trying to solve is to get rid of a constant humming noise in the back when I turn the amp on which, according to a friend, is caused by the converter. It happens when there's no instrument plugged in and only gets louder as I apply guitar effects or increase drive/gain.
I'm considering buying a noise suppressor, but I wanted to know if there are other equipment designed to handle this kind of setup or get any advice on other options.