Do the insulating rings on a jack actually do anything?

[ViralRazor]

Well I was bored, I had a scissor and a crappy pair of old inner ears. So I basically cut off a insulating ring (one of those black thingoes on the jack) and I was surprised to find metal underneath.
 
As metal conducts all the way through, what purpose do these "insulating" rings have. Current is going to travel from 1 part of the jack to the entire jack due to the fact that its all metal.
 
However I'm a complete noob with audio so I'm wondering if anyone could tell me if these rings have any purpose whatsoever.
 

 
Heres what I mean by metal underneath the ring. See the second ring? Notice how its mostly gone and good ole conducting metal underneath.

 

[Steve Eddy]

 
What you're missing is the fact that the contacts nest concentrically within each other (sort of like those Russian matryishka dolls) and there is insulation between them. The only insulation you actually see is the insulation between the gaps.
 
This is what a cross section would look lilke with the insulation being the hatched areas:
 

 
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[batphink]

The rings also tell you what kind of plug it is.
 

1. 1 ring - Mono
2. 2 rings - Stereo
3. 3 rings - Stereo and video, stereo and usb, or stereo headphone and mono mic
4. 4 rings - Stereo headphone and stereo mic

 
 

 

[ViralRazor]

The more you know!

So how much would I affect the sound quality if I stripped the visible insulation?

Would it be minimal or generate something like huge crossfeed?

 

[Steve Eddy]

 
Wouldn't have any meaningful effect at all.
 
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[BlackbeardBen]

Quote:

 
Wouldn't have any meaningful effect at all.
 
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Unless you shorted them, that is.  That would be a not so good thing for the amp, although with the inherent short-causing design of TRS plugs I assume most headphone amps are fairly short-tolerant.

 

[Steve Eddy]

Quote:

Unless you shorted them, that is. 

Well sure. But then it's not much fun listening to... nothing.

 
Quote:

That would be a not so good thing for the amp, although with the inherent short-causing design of TRS plugs I assume most headphone amps are fairly short-tolerant.

 
One would certainly hope.
 
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[jcx]

shorting outputs may not be a good idea with some amps
 
Beta22 recommendation is to never "hot plug" TRS -  many other project amps have no current limiting, some op amps ( AD8397) don't have internal short circuit protection