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Arm cable - soldering shield & ground? Please help

Hello Chaps,

This is my first post in this forum even though I bought and sold a few things in Audiogon. I live in the Washington, DC metro area, have been tinkering with audio for almost thirty five years but I am unsure as to what to do in this case.

I would like to replace the original tonearm cable in my Thorens TD147 Jubilee with a Van den Hul M.C. 501 silver hybrid cable that I found in my parts bin. One end has SME RCA plugs, the other is unterminated.

When I built my own cables from scratch I always cut off the shield at both ends but the Van den Hul cable comes factory assembled with the shields connected to the grounds in the RCA plugs.

My question is, do I cut the shield off at the tonearm's end [unterminated] or do I solder the shield with the ground as it has been done with the plugs?

I’m trying to avoid possible hum problems.

Please advise.

Kind regards,

Orazio
f456gt
nsgarch's avatar
nsgarch
2,524 posts
 
(You're gonna hate this) but it depends! I am going to assume you are not talking about replacing the internal tonearm, wiring itself. And you are just going to solder the unterminated end of the 501 to a terminal strip under the TT? If that is correct, then you DO NOT connect the shield to anything at the TT end -- you want it to float. Just hook up the L and R, plus and minus leads to their respective places on the terminal strip so that they connect properly to the cartridge.

There should also be a fifth wire in the 501 set that is separate from the 2 signal interconnects. At the RCA end, it has a spade fitting that connects to the ground lug of the phono preamp. The other end usually connects to the fifth pin of a DIN plug to provide grounding for the tonearm wand and turntable chassis. You will need to find a place on the Thorens to make this connection ;-) although there may already be a ground wire on the Thorens just hanging there, so connect it to that.
f456gt OP
38 posts
 
You got it right, that's exactly what I needed to know, to leave the shield on the unterminated end floating.

Thanks so much for your prompt reply.

Regards,

Orazio
mingles
796 posts
 
My question is, do I cut the shield off at the tonearm's end [unterminated] or do I solder the shield with the ground as it has been done with the plugs?

I’m trying to avoid possible hum problems.

You may want to try it both ways.

When I rewired an RB-300 with a single strand of Cardas 4x33, I grounded the shield that wraps the Cardas wire to the tonearm and then let it float on the RCA end (there isn't anywhere to ground it to anyway since this is DIY cable). I have a second sheath of braided stainless steel over the length of the Cardas cable and it's completely floating. It's probably overkill, but there isn't a trace of hum in my system. I also run a ground wire from the table to the phono preamp. Without that, I get hum.
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