BHK 300 amps with a hum

Is it normal for my new BHK monoblocks to have a low level hum at idle? -I’m not talking about a ground loop hum from the speakers, but rather a low level hum directly from each amp.

Some do, many don’t. My pair of BHK Mono’s hum from new. We discounted DC etc. It is transformer hum. PS Audio had the transformer company make new transformers to get the lowest noise, tested them in Boulder, and then sent them to Australia to be installed in my mono’s. One mono is now silent but the other mono still hums. I can hear the hum when the system isn’t playing music (idling) at my listening seat 3m away. I have been told there is nothing else that can be done. ;(
Another 2 owners have contacted me and said they experienced the same problem. It isn’t very common but it does occur.

I can only hear the faint hum up very close.
I guess it’s normal.
Thanks for the reply

My 300 mono’s have transformer hum, one louder than the other, but not so loud that I hear them at my listening position with no music playing, thankfully. I have heard hum of this level in an awful lot of amps through the years, so I’ve concluded that it is normal.