Major Hum problem

[thejp]

Major hum problem here! It shows up in the recordings and is so loud I can't record.
I have tried:

-Buying a new interface
-Two different power cleaners
-Changing outlets
-Changing computers
-Changing gear

I do not hear it when only using headphones and keyboard (while keyboard is plugged into wall and not hooked up to a computer). There is also a hum coming from my soundbar hooked up to my TV in a separate room.

My house is in a historic district in Atlanta, and was built in the 1920's, however my musician neighbor doesn't have any problems.
The power company came out and said there wasn't a problem from their end (the pole and line to the house).

Considering there's a hum with the soundbar in a separate room, I'm inclined to think it's an electrical issue with the house I'm renting. The electric guy also told me the power lines outside were carrying more power than usual (a main power line to a hospital).

 

[Bobbsy]

Are the sockets in your house 2 pin or 3 pin? A lot of older places (in my memory--it's 35 years since I've lived in North America) only had 2 pin with no ground. If three pin sockets, are you sure the ground is actually connected back to something rather than just there to accept modern plugs.

 

[ecc83]

Are the sockets in your house 2 pin or 3 pin? A lot of older places (in my memory--it's 35 years since I've lived in North America) only had 2 pin with no ground. If three pin sockets, are you sure the ground is actually connected back to something rather than just there to accept modern plugs.

If perchance your mains supply is NOT earthed i.e. it is a "floating" supply do not whatever you do earth any equipment.
To do so would put at risk everyone else on that phase because a fault to ground in your gear would make the whole supply referenced to ground.

Such supplies are found in a few parts of the world but not in America AFAIK, there the pole pig has one side earthed and then you get 120 and 240volt taps.

Dave.

 

[pouxhawk]

Bobbsy asked the required first question for sure.
Take ECC83's advice seriously!
This could be an insurmountable issue and it being a rental certainly limits your options.
That all being said, I just want to go over some of my personal hum hunting checklist. Not on any particular order.
1) All items plugged into the same circuit?
2) Power conditioner working properly? Designed to isolate grounds?
3) Audio signals transformer isolated? Or tried lifting signal grounds (Not recommended)
4) Starting from the computer headphone out, and adding components one at a time to see if there's one hum inducing culprit?
5) Do you have unbalanced audio connections?
6) Cabling in good shape.. broken shields?

The fact that your keyboard doesn't have the issue makes me think that this IS a solvable problem.
Fighting hum isn't any fun. I truly feel your pain. Keep posting thejp. You're not alone.
olduncledino