[leftofthedial]

Why would you not ground an XLR housing to the cable shield, and is
their an accepted best practice for wiring these things. Most the
connectors I buy have a 4th solder cup specifically for this purpose.
I usually don't connect it though. Bad?

[Scott Dorsey]

leftofthedial wrote:
Why would you not ground an XLR housing to the cable shield, and is
their an accepted best practice for wiring these things. Most the
connectors I buy have a 4th solder cup specifically for this purpose.
I usually don't connect it though. Bad?

There is some discussion of this in the FAQ. The traditional procedure
is to ground the shield on the male connectors but not the female ones.
This means when you string cables together, the outer shields of both
cable ends at the join are grounded at a single point (so there is no
little ground loop as would happen if they were both tied to pin 1).

The problem is that is breaks down when you plug the male connectors
into a piece of equipment where the outer shield is tied to pin 1
internally somewhere. See Bill Whitlock's paper on the "Pin 1 problem."
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Julian]

On 6 Jul 2006 10:57:42 -0700, "leftofthedial"
wrote:

Why would you not ground an XLR housing to the cable shield, and is
their an accepted best practice for wiring these things. Most the
connectors I buy have a 4th solder cup specifically for this purpose.
I usually don't connect it though. Bad?

I've seen a couple of times where it does matter.

Julian

[leftofthedial]

Hmm, I read this article just now but don't think we are talking about
the same thing.

My cable is has a shield and a drain wire both bare (one copper colored
and one silver color) and two insulated conductors (one colored and one
clear).

I generally solder the colored wire to pin 2, the clear wire to pin 3
and the silver colored drain wire to pin 1 on both ends. Now I have
the option of soldering the copper colored shield to the housing pin
(or not).

In either event, I am carrying the shield across pin 1 on both ends.
It's the XLR housing I'm asking about.

[leftofthedial]

Sadly, a reading of the FAQ and the Rane article leads me to believe
that I will never understand this. Best, next best, last best etc. My
brain may be too small.

[Mike Rivers]

leftofthedial wrote:

I generally solder the colored wire to pin 2, the clear wire to pin 3
and the silver colored drain wire to pin 1 on both ends. Now I have
the option of soldering the copper colored shield to the housing pin
(or not).

In that case, I'd solder the shield to the terminal that goes to the
shell. That will carry the shield through the shell so that it will act
like conduit. The wire to Pin 1 will tie Pins 1 on both ends together,
which you probably want to do.

Gotham makes some three wire shielded cable and that's the proper way
to connect it. In your case, the drain and shield are probably
connected electrically. Bill Whitlock has something to say about that,
but I cant remember what it is.

[leftofthedial]

Sadly, the Neutrik docs on their website do not address what to do with
the 4th housing terminal. They tell you how took hook up pins 1-3
(like I really needed this information) but don't even mention the 4th
terminal. I went back and check some of my older cables and I'm pretty
consistient in connecting the shield to the shell on both ends. But as
you said, the drain and the shield are electrically connected because
they are bare wire, so I don't know what effect that has....

[Ty Ford]

On Thu, 6 Jul 2006 15:00:05 -0400, Julian wrote
(in article ):

On 6 Jul 2006 10:57:42 -0700, "leftofthedial"
wrote:

Why would you not ground an XLR housing to the cable shield, and is
their an accepted best practice for wiring these things. Most the
connectors I buy have a 4th solder cup specifically for this purpose.
I usually don't connect it though. Bad?

I've seen a couple of times where it does matter.

Julian


ASk the guys in the live sound forum. They seem to have more issues with
cables being dragged and a higher possibility of something untoward happening
if the shell touches the wrong thing while being moved.

Regards,

Ty Ford


-- Ty Ford's equipment reviews, audio samples, rates and other audiocentric
stuff are at www.tyford.com

[martin griffith]

On 6 Jul 2006 14:54:24 -0400, in rec.audio.pro (Scott
Dorsey) wrote:

leftofthedial wrote:
Why would you not ground an XLR housing to the cable shield, and is
their an accepted best practice for wiring these things. Most the
connectors I buy have a 4th solder cup specifically for this purpose.
I usually don't connect it though. Bad?

There is some discussion of this in the FAQ. The traditional procedure
is to ground the shield on the male connectors but not the female ones.
This means when you string cables together, the outer shields of both
cable ends at the join are grounded at a single point (so there is no
little ground loop as would happen if they were both tied to pin 1).

The problem is that is breaks down when you plug the male connectors
into a piece of equipment where the outer shield is tied to pin 1
internally somewhere. See Bill Whitlock's paper on the "Pin 1 problem."
--scott
http://64.70.157.146/pdf/Bondingcableshields.pdf

Heavy stuff, but good, done by the EMC dude at Cadac, Tony Waldron


martin

[Julian]

On 6 Jul 2006 13:16:17 -0700, "leftofthedial"
wrote:

Sadly, the Neutrik docs on their website do not address what to do with
the 4th housing terminal. They tell you how took hook up pins 1-3
(like I really needed this information) but don't even mention the 4th
terminal. I went back and check some of my older cables and I'm pretty
consistient in connecting the shield to the shell on both ends. But as
you said, the drain and the shield are electrically connected because
they are bare wire, so I don't know what effect that has....

I usually don't connect anything to the shell.

I have seen a problem with mic lines over 100 feet in some
environments with some phantom power mics. In that case, connecting
the shell to pin 1 (ground) has proved helpful.

I have also seen problems with panel mounted mic jacks in which
connecting the shell to ground helped quiet things down.

Julian

[anahata]

leftofthedial wrote:
Hmm, I read this article just now but don't think we are talking about
the same thing.

Probably is the same thing...

I generally solder the colored wire to pin 2, the clear wire to pin 3
and the silver colored drain wire to pin 1 on both ends.

Correct.

Now I have the option of soldering the copper colored shield to the housing pin
(or not).

The drain wire is in contact with the shield so they are equivalent.
But that is the problem area. Where two connectors are mated, it is
desirable to have the housings grounded, and the two housings make
electrical contact with each other. It is not ideal, however, to have
both housings connected to the cable shield/drain wire. Ideally one
should be grounded to the cable the other shoud be grounded by contact
with the first one. Hence the suggested convention that you always
ground the male shell but not the female.

In all cases it makes very little difference unless there are
exceptionally difficult interference conditions. In theory with perfect
balanced lines and inputs you wouldn't need any shielding at all.

--
Anahata
-+- http://www.treewind.co.uk
Home: 01638 720444 Mob: 07976 263827

[Richard Crowley]

"Scott Dorsey" wrote ...
There is some discussion of this in the FAQ. The traditional procedure
is to ground the shield on the male connectors but not the female ones.
This means when you string cables together, the outer shields of both
cable ends at the join are grounded at a single point (so there is no
little ground loop as would happen if they were both tied to pin 1).

The problem is that is breaks down when you plug the male connectors
into a piece of equipment where the outer shield is tied to pin 1
internally somewhere. See Bill Whitlock's paper on the "Pin 1 problem."

What about tying pin1/screen to connector shell only on the
female side?

Then there are people who use a capacitor rather than a hard
connection. (People who have problems in hi-RF environments).

[Scott Dorsey]

Richard Crowley wrote:
"Scott Dorsey" wrote ...
There is some discussion of this in the FAQ. The traditional procedure
is to ground the shield on the male connectors but not the female ones.
This means when you string cables together, the outer shields of both
cable ends at the join are grounded at a single point (so there is no
little ground loop as would happen if they were both tied to pin 1).

The problem is that is breaks down when you plug the male connectors
into a piece of equipment where the outer shield is tied to pin 1
internally somewhere. See Bill Whitlock's paper on the "Pin 1 problem."

What about tying pin1/screen to connector shell only on the
female side?

You get the same problem, just on the other end. And also you get cables
that are different from everyone else's.

Then there are people who use a capacitor rather than a hard
connection. (People who have problems in hi-RF environments).

This is a sloppy workaround for badly-designed equipment. But I have
done it too.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."