Help! Is my new McIntosh MA12000 broken?

No, it should not make a loud humming noise. Contact your dealer and have them take care of the problem for you.

Mine is 100% quiet.

I did not have a good experience with Macintosh service when the DAC went out. The factory response was really pitiful. I finally had the DAC module replaced by my dealer.

Not an expert on this, but if the sound is coming from the amp itself I think it means you have some DC on your AC power line and it is making your transformers hum. Look into a DC blocker, I think there are several options out there. ( e.g. HumDinger)

+1, install a DC Blocker to see if that stops the hum. And, if not, Return the amp to your retailer ASAP. Please keep us posted. For example, please this link:

DC BLOCKER

Or, maybe try a less expensive DC Blocker from your local hardware store. 

I had significant transformer hum from my small tube amp when I moved to a new residence years ago. Purchased the Emotiva CMX-2, which completely addressed the issue. Worth a try. 

+1, “Contact your retailer and have them take care of the problem for you”. 

This might be better than my previous suggestion of using a DC Blocker. Your Retailer should know the best way to handle this. Please keep us posted.

unit should be dead silent, return it for inspection and don't accept any BS excuses.

Sounds like a pain but at least the eventual outcome was good. 
 

to those talking DC on the AC lines. Curious…. Can that be measured with a meter or need something like a scope? 

To the op @hifilover87 did you get your problem solved?

He did said he got his money back but was a pain in the ass. That was a couple posts up and it’s removed for some reason.