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Hum after replacing tonearm cable

After replacing my entry-level tonearm cable with the high-end one there is now a very audible hum once the turntable is on and its motor is spinning. Moving the turntable around, away or closer to the phono stage or rotating it 180 degrees or upside down did not make any difference on hum. It is consistant regardless where the turntable is or how far or close it is to preamp or amp. The hum is equally loud in both left and right channels. Is there anything that could be checked or done to fight the hum other than switching back to my entry level tonearm cable?
esputnix
chakster's avatar
chakster
6,144 posts
 
I hope your phono cable is shielded?

Simple tests:

1) Disconnect tonearm ground wire from the phono stage and listen.

2) Connect additional ground wire with stripped ends from your phono groung plug to tonearm metal part and listen.

If the hum is gone let us know is it 1 or 2 or nothing.
esputnix OP
19 posts
 
1. Disconnecting tonearm ground wire from the phono stage did not make even a bit of the difference. With or without the tonearm ground wire bolted to the Ground Post of the phono stage makes no perceivalbe difference in anything. I wonder if this a Ground post or a tonearm ground wire that doesn't ground at all. Should be any hearable difference in hum when we connect/disconnect the tonearm ground wire?

2. The tonearm is SME 4. It looks silverfish plastic (I think it is painted magnesium). I guess I should be able to connect a ground to it safely... Thank you for your suggestions!  
luisma31
516 posts
 
Check the new cable continuity with a voltmeter?
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