>As soon as I turn on both the transformers start vibrating and emit a combined 34db hum which is a little annoying to have as a noise floor. ...
All power transformers are prone to hum, but 34db (@1m?) is too loud. Maybe the transformer is defective or loose - maybe someone dropped it, maybe it got overcooked at one point, maybe it was just a plain old manufacturing defect. In any case, it's nothing you should have to live with, not in this equipment, IMHO. Your warranty is your friend.
But experiment, before you go that route. Make sure you haven't plugged the amp into a UPS by mistake, or anything, for that matter, except a wall socket. Plug in something else with a power transformer into the same socket and see if that hums. Try it in different wall sockets. Try the filtering equipment. Open the amp and carefully put a very heavy weight (a non-conductive, non-magnetic one please) right on the transformer and see if that mutes it. Look for a loose mounting or loose case parts. Make sure you aren't sharing a power line with, say, 20A worth of other equipment - maybe the amp is starving for power and that makes the trans work hard. Make sure someone isn't running MRI equipment right behind the wall of your sterero room, and you aren't in direct line of transmission of, say, a military-strength radar facility.
There's no point in 4-zeros-right-of-the-decimal-THD if you can't hear the blasted music. If these two units (and only these two units), always hum when connected to each other, regardless of where and how you plug them in, then I'm *certain* the engineers at Bryston will want to take these units apart and get to the bottom of it. As a long time Bryston owner and someone who mucks around with circuits, I can tell you that they will be very interested in Why.
