I'm not sure about the power being the cause of the buzzing, but I can tell you what made me decide to invest in some power protection and power regulation hardware.
The place I live is a rented house, and ever since we moved in here I had noticed a strange thing with the power. If you'd use a vacuum cleaner somewhere in the house, you could see the lights dim for just a small period in the entire house when turning the cleaner on. Later on I found this to be the case with all heavy devices. I had it checked by some "expert" but he didn't find anything worth worrying about, which makes sense, since the landlord would have to fix the issue and turn up for the costs.
I decided this wasn't going to be very good for any hardware, so I went out and bought an APC Smart UPS 1000
and connected all my equipment to it hoping it would resolve the issue and protect my machines from the powersurges I noticed in the lights.
Later on I bought a laser printer. When I connect that and turn it on, the lights in my office blink (dim/normal) continuously while the machine starts and initializes. When printing something the same happens. The blinking annoyed me but connecting a laser printer to an UPS seemed kinda silly, since it has some very high power draw peaks. I asked UPC for a solution and they recommended me the Line-R 1200 VA
. I connected the laser printer through that and the blinking is pretty much gone. I can hear the device switching sometimes when I turn on the printer or print pages.
Both devices run completely silent., with the exception of the situation when the power goes out. The UPS makes a buzzing noise then, with an alarm loud enough to wake half the block. The UPS has an array of status LEDs which can light a room at night.
I've been running this stuff for about 6 years now, and they seem to be doing their jobs. The UPS has a tool to graph the input power it receives and has a log where it records certain events. Over the years it has logged undervoltage situations on various occasions, and it once saved me some work because the power failed and it allowed me to shut down my machines gracefully.
The most common flaw with power outlets seems to be the grounding, or lack of grounding. In my years I messed with computers I more or less formed the idea that the absence of grounding can cause a greater risk of failure of equipment, based on some personal experiences and reading experiences from others on various forums. It's hard to prove this matters, but it makes sense in many ways. Grounding is required for UPS operation and surge protection devices, and some of them contain some form diagnostic, mostly in the form of a "Power Good" LED or something fancier specifically to check the grounding.
The only diagnostics I have done myself is to measure the voltage coming out of the outlets with a multimeter, since that is as far my toolbox and knowledge range. I've made one more or less interesting observation by doing so. My parents house is right near a transformer building. When I lived there I measured the voltage to be around 260 volts. I read up on this and it seems this is common. I once had the opportunity to measure the voltage futher down the block in the same street, and did notice it was lower there. So the distance related to the power distribution nodes seems to have some influence on it all as well.
In the recent years I have considered hiring an independent expert myself to look at my power situation, and to install grounding throughout the entire house (as is a standard building requirement these days here). But since I'd be improving a house that's not my own, I am waiting for some spare money to spend on it, and not sure when that time comes
As said I am not sure about the AC power being the source of your problems. I am not sure using an UPS or alike will solve your problems either. But in my situation it seems to have worked nicely in the time I have been using them. It solved some annoyances for me in the first place, and judging from the logged events it seems to have done some good in protecting my equipment as well. I've not had any buzzing hardware (except the UPS on battery mode), but I can't say I had any before I started using the equipment either.
I feel my investment paid off and I'd like to think my computers are happy with the power I feed them, but without me gaining the proper education and equipment, I am not sure I will ever be able to put my finger on hard facts supporting that feeling.
Hope this helps you some.