I just purchased my Rega Brio-r, along with a Rega DAC, a couple of weeks ago. Love the sound now that it is broken in, but I also have this buzz/hum. Mine is at 60Hz since I am in the USA. It is a smidgen lower then a concert "b".
Some good info.. if I turn off my powered sub woofer the hum is not as loud. The hum starts fairly loud when I power on the amp, but gets much quieter after about 10 seconds. After warming up it settles into a volume that I can easily hear with my ear about 12 inches from the speaker. The hum is louder in my left channel than the right. I tried using a different power strip and also plugging straight into the wall, and believe it or not I think one of my power strips causes it to be a little louder than the other, so I am now using the quieter one.
I can get OCD about things like this, but here's the thing.. Now that I am tuning into this hum and trying to eliminate it, it has become obvious to me that my whole friggin house is full of the exact same 60 Hz hum. As I sit here in my music listening room with the Brio-r powered on and no source flowing through it, I am about 8 feet from the speakers. I cannot hear the hum through the speakers at all, but I can clearly hear the same dang hum coming from my refrigerator in the other room, and also from the furnace (air handler) that is blowing right now.
I live in a high end custom house that I built 7 years ago, and I did not install a generator. Where I live we have somewhat frequent power outages due to thunderstorms. When the power goes out, it is totally quiet in this house with no 60 Hz hum at all. But when the power is flowing normally everything hums all together - the fridge, the elevator, bathroom fans, the heater, the air conditioning units - everything.
So while the OCD part of me wants to get this amp to sing with no hum, I have to just chill the heck out because I can't stop the rest of my house from humming. I'll just resort to headphones when I can't take that concert B anymore. Kinda sucks, but I'll take this over living in a tent!
I am going to try this Brio-r with my old Boston Accoustics A 40 Series 2, and see if the hum volume changes at all.