Continuity is vital...
Hello, As mentioned above, check your TT's ground connection to the RX. If that is solid, sources your TT can pickup hum from are things like fluorescent lights(CFLs), power supplies, etc. Try to route your TT's signal leads away from it's and other equipment's power wires. If they have to cross, do so at a right angle(perpendicular) where they cross. Noise can be introduced from a poor connection at the headshell to tonearm junction, or from a poor connection between the cartridge and signal leads. Check/clean/secure the connections from the cartridge-headshell-tonearm-TT's interior-signal leads(patch cables). You will likely find the trouble somewhere there. Good luck. -discreteouts
PS Don't rule out the TT's patch cables, defective ones can be a common cause of hum. If the hum comes from only one channel, swapping the L/R leads can help narrow your choices.