Fifth wire on my cartridge?

the thin end of the wedge
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reis99
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Fifth wire on my cartridge?

Post by reis99 » 30 Oct 2019 01:23

Hi, i've noticed that most or all cartridges have 4 wires but for some reason mine has 5? If i want to upgrade to an AT95E cartridge can i do it?

Here's a couple of photos, i'm referring to that fifth black wire.

https://drive.google.com/file/d/17-9sD6 ... emuEY/view
https://drive.google.com/file/d/16zpEUS ... 4phds/view


I'm still an amateur so i'm in doubt here!

Thanks.

reis99
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Re: Fifth wire on my cartridge?

Post by reis99 » 30 Oct 2019 01:25

Do i need to change also the headshell?

circularvibes
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Re: Fifth wire on my cartridge?

Post by circularvibes » 30 Oct 2019 02:32

The fifth wire is a shield connection. It is uncommon to see this on an SME typw headshell. You can use any modern 4 wire cartridge. The fifth wire goes between the cartridge and the shell, not actually connected to the cartridge. Wire the other 4 as normal.

billshurv
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Re: Fifth wire on my cartridge?

Post by billshurv » 30 Oct 2019 10:54

I've never seen that before, but need to retrofit that on some of my headshells for some tests.

reis99
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Re: Fifth wire on my cartridge?

Post by reis99 » 30 Oct 2019 13:57

So it's safe to connect a 4 wire cartridge and leave that one out?

billshurv
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Re: Fifth wire on my cartridge?

Post by billshurv » 30 Oct 2019 13:59

yes. perfectly safe.

reis99
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Re: Fifth wire on my cartridge?

Post by reis99 » 30 Oct 2019 14:16

awesome then, just out of curiosity what is that cable supposed to shield from?

billshurv
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Re: Fifth wire on my cartridge?

Post by billshurv » 30 Oct 2019 14:29

The MM generator needs to be shielded from electric and magnetic fields, otherwise it will be an excellent antenna. So most MMs (other than Grado) are placed in a metal box. This box needs to be grounded. Normally this will be via one of the gnd pins on the cartridge. In this case a previous owner has decided to ground it seperately and has bent up the tab that connected to one of the pins to solder his own wire on.

noisefreq
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Re: Fifth wire on my cartridge?

Post by noisefreq » 30 Oct 2019 14:40

I've seen similar wiring on a Sansui headshell.
It tied the cartridge, arm and base ground together.
Seemed a bit overkill but when disconnected it hummed.

Pauw
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Re: Fifth wire on my cartridge?

Post by Pauw » 30 Oct 2019 16:24

Some Philips cartridges and turntables from the early days have five connections and five wires . :D

reis99
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Re: Fifth wire on my cartridge?

Post by reis99 » 30 Oct 2019 18:00

Thanks all for the replies :) very helpful

BMRR
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Re: Fifth wire on my cartridge?

Post by BMRR » 30 Oct 2019 19:48

I have seen this on early ELAC Miracord headshells as well.

lini
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Re: Fifth wire on my cartridge?

Post by lini » 31 Oct 2019 04:57

Maybe that headshell was intended to provide an extra ground contact option to the generator shell of an MM/MI cartridge with non-conductive mounting frame and disconnected generator shell to right or left signal ground connection for use with phono stages with balanced input.

Greetings from Munich!

Manfred / lini

billshurv
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Re: Fifth wire on my cartridge?

Post by billshurv » 31 Oct 2019 09:30

Given how rare balanced input phono stages are I wonder what the story was behind this.

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