What's that little piece of metal for, anyway?

keith.rogers

Well-known member
I've noticed in a few XLR male ends (in microphones only, perhaps) that's there's a little piece of metal visible. Is it just something that some makers put in there to prevent rotation? Why is it there?

I was dusting off an old mic to consider selling it, and I noticed that it actually has a tiny piece of tape over that. I have no idea if it was original, but my guess is that someone put it there, and I wonder if they did it for a [valid] reason or if they were just chasing some problem and did it for no real [electrical/engineering] reason. (I could take it off and see what happens, but, then, I would like to sell the mic in its current, working condition.)

Attached is a pic from a [different] mic where it's not taped over.
 

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Gtoboy

Well-known member
I've noticed in a few XLR male ends (in microphones only, perhaps) that's there's a little piece of metal visible. Is it just something that some makers put in there to prevent rotation? Why is it there?

I was dusting off an old mic to consider selling it, and I noticed that it actually has a tiny piece of tape over that. I have no idea if it was original, but my guess is that someone put it there, and I wonder if they did it for a [valid] reason or if they were just chasing some problem and did it for no real [electrical/engineering] reason. (I could take it off and see what happens, but, then, I would like to sell the mic in its current, working condition.)

Attached is a pic from a [different] mic where it's not taped over.
Ground point for metal shell (through the screw). It is inserted from that side to keep it from being pulled toward the inner shell and causing a short. I don't think that even if it backed out slightly that it could possibly touch something on the outside that might short or otherwise cause damage so you should be good.
 

keith.rogers

Well-known member
Ground point for metal shell (through the screw). It is inserted from that side to keep it from being pulled toward the inner shell and causing a short. I don't think that even if it backed out slightly that it could possibly touch something on the outside that might short or otherwise cause damage so you should be good.
Ah. I just confirmed that the screw and pin 1 are connected. Now, why tape over the exposed part? Who knows. But, I'll leave it alone, since it's working.
 

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The tab is usually continuous with the chassis of the XLR barrel and, therefore, the chassis of the microphone or input device.

As in spantini's picture, it's often bridged to pin 1.
I guess there are cases where you might want the microphone ground isolated from equipment chassis.
 

rob aylestone

Well-known member
There used to be a problem (perhaps still is) with pin 1 and the ground - connecting the two caused circulating currents producing hum - it was a problem that was fine on some kit and the kiss of death on others. Shure were keen on that XLR insert with the tag inside.
 
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