Help me solve another speaker hum thread :)

The first thing I would do is make sure the cables are routed correctly. It sounds like cables are plugged, dropped and forgot. 1/2 the time I can fix noise in a system with routing cables at 90 degree crossing and nothing closer than 1/2". Over, under or along side. I’ve done it that way for 45+ years. My systems are OLD and new all have no noise (not low) NO NOISE. You pick the source and turn it all the way up. If you stay still and don’t jump up and down in the room with the TT selected even that is quiet. ALL valves too. C20, ZP3, V12R. Dark background..

I’d look there first.. Tubes be careful what you have close to what.. Power supplies from Laptops and Cable boxes can be noisy too.

220/40 is an option too for the 901s and use the balanced side. What are you using for a Pre and Source?

Regards

Can you try it all on one of your four dedicated lines? 

Check the routing and connections of the cables as @oldhvymec  said and then pull and re-seat all the tubes.

 "Sonus Faber Aida’s with 2x McIntosh MC901 monoblocks."

Con$iderable investment there...

Noticeable hum at ANY level except at neurotic audiophool distance(press ear against the speaker) would not be acceptable IMO.

Get your dealer involved, he wouldn't want to see your gear come back.

Try all the simple things as suggested-reseat every possible connection. 

@noromance to clarify, the speaker still hums when ONLY the MC901 is powered and connected to speaker via speaker cables. No other cables or devices are connected, powered, or even plugged into an outlet. Nothing else is on the circuit.

I checked cable routing, nothing is touching. I tried 2 other dedicated outlets, no effect. I reseated tubes, no effect. I even swapped all tubes with the other MC901, no effect. I swapped power cords, no effect. I disconnected and reconnected speaker cables, no effect. Did not try swapping speaker cables with other speaker, maybe will try tomorrow.

At this point I think there is something wrong with the amp. It weighs 180 lbs though, too heavy to move by myself to the other speaker to see if the issue will replicate.

Guess I’ll contact my dealer.

Just to be clear, this is definitely an issue that needs to be corrected (i.e. a serious issue?)? Or will my dealer shrug and think I’m being a "picky customer"? I don’t know how big of a dealer speaker hum caused by amp is. 

And should I have my dealer address both amps? Even the one that has a barely audible hum with my ear less than an inch away? Or just the louder one that I can hear hum from 6 inches away? Thoughts?

Thanks all