Agreed. Fully balanced I don't have an issue. Once in a while I would hear a buzz for like 2 seconds and then it would go away. However, I wanted to be able to switch between my open back and closed back cans easily, which is why I decided to connect the Sundara to the SE output. Honestly, it sounds fine to me and I don't get any noise if I'm only using the SE output (this is all with balanced input). However, the moment I use both outputs, then it's noise city.
I hear you. it becomes really loud when i put my finger on the chassis. When i'm not touching the chassis, the sound is barely audible. Annoying, but I guess that's what you get with an ungrounded $199 amp!