Hum coming from Turntable

The simple answer to your question is yes. All of the above can create hum. Usually it is a ground loop somewhere. Is it a high sound buzz or actual low pitched hum? If the latter, that is a ground issue usually. You didn’t mention your phono stage or other equipment. If tubes are in the mix anywhere that can be your source of noise. If low enough to not be heard with a low volume sometimes it can be lived with. Chasing down a hum can be nightmarish. As mentioned, try different cables first, possibly even the PC if that is possible. Make sure you don’t have any wall warts in your power system. Could also be your phono stage settings or cart in general. Lots to play with. Good luck!

Thank you all for the awesome advise, it helps alot.  I want to ask if the body of all cartridges has to be grounded or certain cartridges doesn’t need the body to be grounded to the head- shell?  Also, can i say that all turntable tonearm & base has to have ground loop with the turntable body?   What happen if just the turntable by itself has a ground loop but the tonearm doesn’t or vice vera?   Will this cause hum noise?  

I would run all grounds to the same point.
If the cartridge is plastic or wood, then I am not sure how grounded they are??

If it is inducted field, rather than a ground loop, then it can get more complicated… but moving the switching supplies to another power strip might provide a data point?

Try this. Gently move your cart wires a bit with your finger when everything is turned on and the tone arm is “home”. See if that changes anything. I had ground issues for quite awhile and found that I had to have anything the turntable was connected to plugged into a single outlet via a power block of some sort. I currently use a Shunyata hydra which is great. Overall though, the ground issues I had related to the phono stage and it’s position relative to the tone arm.