2. analog
  3. 165361-151430

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
mijostyn's avatar
mijostyn
8,152 posts
 
You need a meter to figure this out. I suspect signal negatives are being shorted to tonearm ground. Some tonearms do this. Check ground continuity of the cable. It should be isolated from the signal negatives. Do the same at the tonearm. If the tonearm is in reality a 3 wire arm then you will have to use the old cable or do significant surgery to the new one. 
chakster's avatar
chakster
6,144 posts
 
I thought you arm was rewired internally too. 
Or you are talking about external cable only? 

esputnix OP
19 posts
 
The cable that hums is used. It was purchased on Ebay. The issue turns to be behind the broken ground wire. There is a crack right where it meets the spate connector. I wonder if it would be OK to just detach the spade connector from the ground wire, open the wire insulation at the end and wrap the exposed ground wire around the Ground Post of the phono stage? Would it be any side effects in exposing the ground wire or it has to be terminated by spade connector?
vinylzone
288 posts
 
That would work fine.
chakster's avatar
chakster
6,144 posts
 
In external phono cable, especially  used one, the problem can occur in the soldering joints, it can be inside RCA or DIN, each connector can be inspected and re-soldered. 
More to discover