EDIT: This makes so much more sense than what I said.The PSU on my new MBP does this.
It's normal, though it could have been designed out by Apple.
The change in noise when you do something on the computer is the PSU adapting the amount of power being delivered.
Please tell me you meant to write TL200 and not 200if youre kinda still prickly on the subject i suggest you get a extender with a fuse inside it. That way if your power outputs go up where your adapter cand adapt and fail the actual power socket will fail instead of your AC adapter which costs 200 euros in Turkey.
Check your electric-socket earth connection. The buzz is because, a low voltage is passing through your body for earthing.Well the first thing, if you press it up against your ear, can you hear a buzz. And second, when the computer is on, does the tone of that "buzz" change when you move you hand on the trackpad?
I'm experiencing some very weird stuff here.