Noisy Mains, and how to tackle it

Hi,

ever since moving into my current place I have been plagued by a certain type of glare in the high frequencies. The first suspects were room acoustics (too much glass) and the gear itself (brighter than average). As I have learned is that while both were indeed a part of the problem, most of the problem is caused by a very noisy mains. 

Why am I sure about this? A couple of weeks ago, one of my friendly dealers dropped a parallel mains filter which effectively removed the glare. Unfortunately the demo unit, a Shunyata Typhoon, is far too bulky and silver to ever land in the living room.

Any suggestions on how to get rid of the noise in a more discreet way? I’m fully aware of the “don’t use mains conditioning with Naim” doctrine and already have a dedicated spur for the Hi-Fi.

Thanks!