I just picked up a couple of 1KW isolation transformers. They're mounted in a thick steel box. I haven't looked inside yet to see whether they have any other kind of line conditioning, but I'm assuming not. When I plug them in, whether or not there is any load, they vibrate and buzz very loudly (for a transformer at least). Is there any way of getting rid of this ? maybe by adding an AC filter before it or something?
thanx
thanx