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SME 20/2 Finger Lift Hum

On my SME 20/2 fitted with a Lyra Argo i, there is a hum whenever the finger lift is touched, but very quiet otherwise, and importantly, when the record is playing. Has anyone encountered something like this and figured out how to correct it. All possible ground combinations have been tried with no change. Again, the hum is only apparent when the finger lift is touched. Thank you for your help.
rsnoceanview
rgurney
279 posts
 
As you mentioned, it is a grounding issue. Is it an SME arm? Could you list your phono-pre and preamp?
fromunda
146 posts
 
try pulling tt ground wire off its post.see what happens.
Ag insider logo xs@2x
rauliruegas
12,786 posts
 
Dear Rsnoceanview: IMHO is a problem with an ungrounded tonearm or/and TT. Even that you already try every ground combination could be that the ground wire in the tonearm is ( for whatever reason ) not soldered.

I think you have to check for continuity with a multimeter as other ground connections.

Regards and enjoy the music,
R.
lewm
12,461 posts
 
IMO, if there were an overall issue with grounding the tonearm (i.e., if there were a potential difference between his tonearm and his phono stage, for example), the hum would be audible at all times, whether or not the OP touched the finger-lift.
larryi
3,718 posts
 
Unless the person touching the arm was also simultaneously touching another another component which has a different potential, I don't see how this is a ground loop. It seems like the person's body is acting like an antenna.

The easiest solution would be to cover the armlift if this really is a problem (perhaps shrink wrap with heat applied directly to the wrap and not to the cartridge itself).
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