2. analog
  3. 191557-183416

Turntable Hum And Channel Drop

I got a new Origin Live Silver tonearm for my SOTA Star turntable about six months ago and it sounds great.  About two weeks ago I noticed a faint hum, but wrote it off as HVAC noise from the neighbors house.  The hum grew ore noticeable a few days ago, and now the left channel fades out at about 1 1/2" into the record, and returns at about 2 1/4"  I raised the tonearm with the motor on and moved it over the top of a record ,and can hear the hum increase and decrease in volume as the tonearm moves over the record.  I checked all of the connections and they are fine.  I swapped RCA cables from left to right and the channel drop then goes to the right channel.  Grounds are all snug.  Any thoughts on what's going on? 

 

For the record I have a Hana EL cartridge and a Jolida JD-9 phono amp.  Thanks in advance for your input.

jrcotner
lewm
13,174 posts
 

Star Sapphire has motor under the platter, I think. If so, problem could be EMI from the motor. Some cartridges are more sensitive than others, but I don’t know why the problem evolved from nothing at first. Try shielding the motor with even a piece of aluminum foil placed between motor and platter. Ground the foil.

jrcotner OP
68 posts
 

Thanks for the info.  At a pretty consistent point when the tonearm travels across the record, the left channel sound quickly gets quieter then is gone.  And it comes back when the tonearm moves an inch or so further into the record.  What would be a suitable way to ground the aluminum foil?  Would alligator clips soldered to a length of wire work?

russ69's avatar
russ69
3,523 posts
 

Got to be the wiring.

jrcotner OP
68 posts
 

Do you think a wire has shorted?  If so, what could be the cause?  I haven't moved or handled the tonearm or turntable at all since this has started, just normal record playing.

lewm
13,174 posts
 

Yes, alligator clips would be fine just to test the hypothesis. 

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