what makes a good external tonearm cable.

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karma67
Posts: 194
Joined: Sat Sep 08, 2018 12:19 pm

what makes a good external tonearm cable.

Post by karma67 » Sun Apr 28, 2019 9:47 pm

looking for you views on construction methods,shield and wire type,ie 4 conductor from din then split into 2 for the rca's or 2 runs of 2 core to rca's,ground wire connected to shield? floating shield or connected at 1 source end only.
whats your view?

sq225917
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Joined: Tue Jan 22, 2013 9:28 pm

Re: what makes a good external tonearm cable.

Post by sq225917 » Mon Apr 29, 2019 12:55 am

Shielding, end to end from arm pillar to sockets at pre amp, use xlr plugs, they have fixed impedance and continuous shielding from the metal bodies. I just use what's on my Kuzma arm now, but used to run two pairs of twinned silver in metal braid all covered in copper foil on my previous Rega and lp12 decks. Totally noise free.

If your going to mod the paradise, use xlr sockets, keep cart plus and minus on pins 2 and 3 and use pin 1 as the shield and connect this to paradise chassis. Do not connect signal minus to chassis, the paradise signal is floating. Keep it that way.
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YNWaN
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Re: what makes a good external tonearm cable.

Post by YNWaN » Tue Apr 30, 2019 10:59 am

Traditionally arm cables are expected to be very low capacitance and this is also why they are rarely much longer than a metre in length. However, the need for very low capacitance is primarily an issue with Moving Magnet cartridges and much less relevant with Moving Coil designs.

The other primary issue regards shielding and it is also (almost) universally accepted that an arm cable needs to be well shielded and the vast majority are made from coax (usually two discreet runs). Part of the problem regarding shielding is that a SUT is quite often used (with MC cartridges) and these are notoriously sensitive to RF and hum.

Personally, I am so pleased with the performance of my ‘homebrew’ unshielded interconnect that I may try something similar with an arm cable.
Mark

karma67
Posts: 194
Joined: Sat Sep 08, 2018 12:19 pm

Re: what makes a good external tonearm cable.

Post by karma67 » Tue Apr 30, 2019 4:52 pm

i think you may get issues with no shielding,i'll give you an example,i bought a tonearm cable from a well known forum cable guy,i found i got some hum when si installed my paradise,it lessened if i twisted the paradise to the right a bit which i thought was due to it being near my valve amp,by chance i made a tonearm cable up using morgami 2549,no hum what so ever,when i compared the the 2 cables i found the one i bought was 4 conductors split into 2 for the rca's. the 2 split runs had no shielding,just cable sleeve only about 150mm but it was enough to introduce hum.

sq225917
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Joined: Tue Jan 22, 2013 9:28 pm

Re: what makes a good external tonearm cable.

Post by sq225917 » Tue Apr 30, 2019 8:51 pm

Interesting to hear that Jamie. I often wonder where any noise comes from as I build them all the same, all floating signal path, and they are all utterly silent at mine.
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YNWaN
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Re: what makes a good external tonearm cable.

Post by YNWaN » Tue Apr 30, 2019 9:17 pm

Oh, which ‘forum cable guy’ was that may I ask?

The problem with shielding for arm cables is that they carry such a tiny signal. The Mogami you mention is one of the most popular, and successful, cables for this purpose. In fact, after much experimentation, the maker of my own arm (the Javelin) chose to use the same Mogami.

I see you have asked the same question on AoS and I would agree that flexibility is important. However, I would also say that it is important to consider how the cable is anchored at the turntable - this is an issue that is often very poorly considered by manufacturers and installers.
Mark

sq225917
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Joined: Tue Jan 22, 2013 9:28 pm

Re: what makes a good external tonearm cable.

Post by sq225917 » Wed May 01, 2019 8:12 am

Agred, you need a physically robust, yet decoupled mount at the deck and ideally one that has shielding from arm bottom to the end of the headshell.

I assume jamie means the Greek guy.
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YNWaN
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Re: what makes a good external tonearm cable.

Post by YNWaN » Wed May 01, 2019 12:24 pm

I think you mean Yannis Tome, but all his arm cables seem to be shielded designs:

https://www.shop.back-promo.co.uk/DIN-B ... 40769.aspx
Mark

sq225917
Posts: 973
Joined: Tue Jan 22, 2013 9:28 pm

Re: what makes a good external tonearm cable.

Post by sq225917 » Wed May 01, 2019 1:53 pm

Ah, ok.


Who is the cable from Jamie?
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