XLR Shell Connection not wired in XLR cables?

[DanielleOM]

A friend was just looking at some XLR microphone cables purchased in
recent years where Neutrik connectors were used. These came from
various manufacturers where you would expect a quality product.

On none of the cable the connection for the shell casing was wired.
(They were the same way at both ends)

She tells me years ago, the shell was always wired to the shield.


Has there been a change in wiring and shield standards?


Danielle

[Ty Ford]

Post by DanielleOM
A friend was just looking at some XLR microphone cables purchased in
recent years where Neutrik connectors were used. These came from
various manufacturers where you would expect a quality product.
On none of the cable the connection for the shell casing was wired.
(They were the same way at both ends)
She tells me years ago, the shell was always wired to the shield.
Has there been a change in wiring and shield standards?
Danielle

Live sound folks tell me they don't want the shell connected to anything in
case the shell comes in contact with something nasty electrical during setup
or teardown.

Regards,

Ty Ford

Try my new blog; http://tyfordaudiovideo.blogspot.com/
Try my audio sample archive: http://tinyurl.com/796z25d
Try my gear reviews: http://tinyurl.com/79q797r

[Les Cargill]

Post by DanielleOM
A friend was just looking at some XLR microphone cables purchased in
recent years where Neutrik connectors were used. These came from
various manufacturers where you would expect a quality product.
On none of the cable the connection for the shell casing was wired.
(They were the same way at both ends)
She tells me years ago, the shell was always wired to the shield.

In that case, if a device on the other end dumps A/C to case
ground, the shell on your end could become live.

That's bad. If the shells are isolated, that won't happen.

Case ground is not signal ground.

Post by DanielleOM
Has there been a change in wiring and shield standards?
Danielle

--
Les Cargill

[Phil Allison]

"DanielleOM"

Post by DanielleOM
A friend was just looking at some XLR microphone cables purchased in
recent years where Neutrik connectors were used. These came from various
manufacturers where you would expect a quality product.
On none of the cable the connection for the shell casing was wired. (They
were the same way at both ends)
She tells me years ago, the shell was always wired to the shield.
Has there been a change in wiring and shield standards?

** There are plusses and minuses involved.

When XLR plugs are fitted into a socket, the metal shell is *normally*
grounded to the metalwork of the device - be it a desk or a microphone.
Sometimes, the fit can be lose and hence the ground connection intermittent
or non existent, particularly at the mic end. This may cause a clicking
noises as the connection makes and breaks.

OR if the mic user holds onto an ungrounded shell, a buzzing noise can
result. Grounding the shell to the cable shield fixes both of these.

OTOH if an XLR lead with grounded shells at both ends is used to connect
two pieces of gear, both of which are grounded to the AC supply - then
this can cause a hum loop to be formed.


.... Phil

[Rupert]

Post by DanielleOM
A friend was just looking at some XLR microphone cables purchased in
recent years where Neutrik connectors were used. These came from
various manufacturers where you would expect a quality product.
On none of the cable the connection for the shell casing was wired.
(They were the same way at both ends)
She tells me years ago, the shell was always wired to the shield.
Has there been a change in wiring and shield standards?

Having pin 1 wired to the shell can offer extra protection against RF infiltration. However, due to a lot of improperly implemented internal grounding schemes of various gear, it can be a source of nasty ground loops. All it takes is one device in your rig with a pin 1 problem to make your whole system buzz. Also, if the shell comes into contact with other grounded devices or shells, it can again introduce loop noise from the additional ground path, especially if the ground paths are from different power service panels. Generally it is better to not connect the shell to pin one and let it float. I don't believe any cable manufacturer ties pin 1 to the shell anymore. The ones I've run into get that jumper cut.

[geoff]

Post by DanielleOM
A friend was just looking at some XLR microphone cables purchased in
recent years where Neutrik connectors were used. These came from
various manufacturers where you would expect a quality product.
On none of the cable the connection for the shell casing was wired.
(They were the same way at both ends)
She tells me years ago, the shell was always wired to the shield.
Has there been a change in wiring and shield standards?
Having pin 1 wired to the shell can offer extra protection against RF
infiltration.

Only if equipment end is not well designed. Alternatively in the case of
daisy-chained XLR cables you will have a few inches of floating 'screening'
(the length of the connectors) at the centre join(s).

geoff