Hum coming from Turntable

holmz… my household grounding is excellent, all of the ground are properly attached.  
Motor and speed controller are both unplug, i still get a hum noise.  

Fyi… i am using a Forsell Air Reference and Air Tangent tonearm.   The table materials are acrylic and wood, and the tonearm is made of plastic and aluminum with Rca output for the Tonearm.  

Cleeds….just bought the TT recently, i had 3 phono stages to swap out to see if i can back track the problem, with the same results.  It’s for sure the noise is coming from the TT or phono cable. 

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?