What is your amp sitting on? I had a similar problem with a more or less new RM-10. It was my first tube amp as well and I could hear it 10 feet away. I had it sitting directly on a piece of ply on spikes on a rug over concrete. I believe it was resonating with the ply and amplifying the existing hum--and it was annoying as hell. I happened to have some herbies tenderfoots I wasn't using so on a whim I stuck them underneath the amp. Problem solved. I can still hear the same hum if I stick my ears right up to the amp but it's no longer audible from my seating position or even 2 feet out. Nothing magical about the tenderfoots, because I switched them out (tonight as a matter of fact) with some audio technica footers I have and same result: quiet. Try it ASAP. I suppose trying a different platform might work as well.
If it doesn't work then, as most everyone has said (and obviously correctly), return it.
If it doesn't work then, as most everyone has said (and obviously correctly), return it.