Hum coming from Turntable


I need help in tracking a slight hum on my turntable.   I did narrow it down, and the cause of this would be my turntable.   Is this due:

1) cartridge not grounded properly 
2) cartridge wires are loose
3) turntable grounding is bad 
4) phono cable not properly shielded

Can any members/technical person that work on turntable can help me out.  Much appreciated!
128x128zipost
My hum was solved by using better shielded RCA cables.

Easy to diagnose if you have spare RCA's to try out.  
My tonearm wiring insulation became worn, made a slight intermittent hum, wiggled the wire, found it, being re-wired now.

you can use any common wire for a separate ground wire, thus you can substitute any interconnect cable you know does not hum to prove your phono cable is not the problem (or is, unlikely). you can use the phono cable for an interconnect (omit the ground attachments, another way of proving it’s not the cable.

cartridge wires: while on, simply touch end of joint of the wire on the pin (making a good connection) with a small plastic handled screwdriver. one at a time. hum changes? goes away? then remove with needle nose pliers, tighten, re-install. Or, just remove/tighten/reattach, never hurts to be sure.

keep in mind: whenever you move a cable or any piece of equipment, the other end? adjacent cables both ends?


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?