Not sure if someone directly answered the question. Using Digital out's will eliminate line noise, AC hum.....However if something else is causing the AC hum, like any other two pieces of hardware, like a lamp, TV, etc, you will always have the hum coming out of your set-up.. Even though it was recorded clean. Getting one power strip and plugging all instruments, equipment you use into it, can sometimes clean things up.
The cheapest way out is to one by one, eliminate the sound plugs of your equipment, you can buy adapters (a 3 prong female socket, and 2 prong plug)..
an uninterruptible power supply, is a good answer to this. Computers are more susceptible to dirty AC. I had my Mac die twice, I had a warrantee with a 3rd party, they came to my home to fix it. The 2nd time I got a 50 something guy, who had a lot more experience, than the first repairman, who just swapped a board. The 2nd man discovered the old wiring in my building actually had 5 volts on the ground.
My Keyboards, Yamaha and Korg, could deal with it, but after about 100 hours of use the computer.
The safest thing to do is get a UPS - this also cleans the AC, and compensates for voltage fluctuations, in the AC coming into your house, which may be prone to issues, if you live in an old building, or a rural area.