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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
holmz's avatar
holmz
2,328 posts
 
Also add:
5) Magnetic fields caused but inductance loops from household wiring.
That one took me a couple of hours to figure out once. But one should rarely find that if the house is wired with Romex.


Does it do it whether the TT motor is running or not? 
holmz's avatar
holmz
2,328 posts
 
1) Does the cartridge even need to be grounded? The two wires come off if each coil
2) doubtful to be causing a hum
3) Seems the most likely to me

4) I would doubt #4 unless the RCAs were running along side of a power line going into the TT.
zipost's avatar
zipost OP
197 posts
 
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.  
zipost's avatar
zipost OP
197 posts
 
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.  
rdk777's avatar
rdk777
568 posts
 
The Google Wifi was causing a hum for me.  Had to move it farther away from the turntable.

Broken ground inside tonearm was also a cause at one time.



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