Wiring mistakes are quite common, and if you test you will find them in lots of homes and venues. I would be more worried about gear releasing "blue smoke" due to a bad wiring job than extra noise. When I was early on in my path of audio a friend convinced me to start carrying a multi-meter on me to test outlets, only takes 10-20 seconds to test an outlet. If the outlet doesn't give me what I am expecting I don't plug in, so I haven't experienced a lot of "noise."
I do remember being at a friends house that had lots of audible electrical noise (hum, hiss, and more); his house was extremely old and I had the idea that the grounds were not working at all; which is not safe to say the least, electricity is no joke. So it certainly is possible due to bad wiring.
I have found that "dirty power" or "noisy power" also has a lot to do with what devices might be plugged in on the same circuit as well; ie fridges or other kitchen/commercial appliances such as blenders, toasters, or microwaves can have some interesting interactions; also really cheap devices (Ebay special $10 LED's or some such thing) tend to output noise as well, you know the type of product that is so cheap it is probably isn't UL tested/listed.
Moral of the story long as you aren't on the same circuit as your kitchen, don't have absurdly cheap devices on the same circuit, and your wiring checks out you should be fine, and should not have any electrical noise.
To the OP:
1) If you don't enjoy these speakers, find something that you do. The speakers are the biggest factor in the chain by far (well outside of the microphone used on the front end, which is out of your control). Keep in mind your room impacts how your speakers translate. Once you get into a certain level of loudspeaker, they may not flatter certain records or mixes. My "listening system" is some fairly inexpensive vintage British bookshelf speakers that I quite enjoy, there is nothing flat about them, but they are quite pleasing to listen to. My mixing rig is comparatively extremely expensive pair of active monitors. With out a doubt the monitoring rig is more high-end, but it will pull apart a poorly mixed album in a way my other system won't. I enjoy listening to music on them both.
2) Your ears are unique to you, and they are biological, how we hear is a little different every-day. How we hear changes based on if we have had a cold, and what kind of noise exposure we have had etc. You may also find that you need to "train them." For more on this see my next point.
3) With respect, do you know what you are listening for? Doing a little listening and learning could be helpful for you (Harmon How To Listen, Train My Ears etc). Or hanging with someone who can listen to the same thing in the same room, and show you what they love listening to, and why. To the point I had an "audiophile" friend who complained what a rubbish recording Vince Gauraldi Trio's Charlie Brown Christmas album was, I had to explain that the "white noise" he was hearing was actually the drummer using brushes and that this is a common technique utilized by jazz drummers.
You don't know until you know I suppose!