Proper use of XLR connectors
Mark Rehorst
in studio equipment:
Does the cable shield connect to pin 1 or to the chassis ground?
At which end of the cable (or both)?
Thank you.
MR
Mark Rehorst
studio equipment?
1) Are they used with an unshielded twisted pair, or with a shielded
twisted pair (shield over a twisted pair), or with twisted shielded
pairs (shielded wires twisted together)?
2) Is the shield (if used) connected at the sending or the receiving
end of the cable or both?
3) Does the shield connect to the chassis lug or to pin 1 of the XLR
connector?
Any help is appreciated...
Thanks
MR
André Huisman
<36686054...@fmi.fujitsu.com>...
>Two simple questions regarding the proper use of XLR connectors as used
>in studio equipment:
>Does the cable shield connect to pin 1 or to the chassis ground?
Pin-1
>At which end of the cable (or both)?
Both.
Talking about normal 1:1 connections (no fancy balanced -> unbalanced or
visa versa stuff).
Some older (tube) amps used to connect the chassis of the XLR (that's where
that extra tab is for) to ground as well. Nobody (?) does that nowadays
though.
André Huisman
New Line licht & geluid
XXXne...@usa.netXXX
http://www.xs4all.nl/~newline/
remove X-es to reply
--- pardon my French, I'm Dutch ---
Jerry G.
contact is chasis or electrical ground.
--
Jerry Greenberg
http://www.zoom-one.com/electron.htm
=============================================
Quick Reply To: jerr...@hotmail.com
We Specialize In Elecronic Componets
WebSite 1: http://www.total.net/~jerryg
Website 2: http://www.zoom-one.com
If It Works, Don't Fix It !
If It Don't Move, Slap It !
If It Don't Make Noise, Shake It !
If It's Broke, Then Fix It ... !
If You Don't Know How To Fix It, Give It Out !
============= Message Separator ================
Mark Rehorst wrote in message <36686054...@fmi.fujitsu.com>...
|Two simple questions regarding the proper use of XLR connectors as
used
|in studio equipment:
|
|Does the cable shield connect to pin 1 or to the chassis ground?
|At which end of the cable (or both)?
|
|Thank you.
|
|MR
|
|
Pamela Hughes
Take a look at application note 110 on this page:
http://www.rane.com/library.htm
Generally you use a shielded twisted pair with the shield
connected to pin one, or a star-quad cable with both wires of one
color connected to one pin and the other two connected to the
other pin (just be consistent on both ends of the cable) and the
shield to pin one. You could also fit a small ceramic or silver
mica cap between pin one and the plug body to allow for a
frame-ground for radio frequency interference picked up by the
shield, though probably not needed for short runs
Scott Holderman
>
> Can anyone tell me how XLR connectors are used in typical recording
> studio equipment?
> 1) Are they used with an unshielded twisted pair, or with a shielded
> twisted pair (shield over a twisted pair), or with twisted shielded
> pairs (shielded wires twisted together)?
...Usually a shield over a twisted pair. A mumber of twisted shielded
pairs
may be utilized in a snake.
> 2) Is the shield (if used) connected at the sending or the receiving
> end of the cable or both?
...If both ends are balanced, the shield should only be connected at one
end.
Convention generally indicates connecting it at the receiving (input)
end of
each device but sometimes the other end is used.
> 3) Does the shield connect to the chassis lug or to pin 1 of the XLR
> connector?
...It depends on the internal AC grounding scheme of the device.
Sometimes just
pin 1 is used, sometimes it is also tied to chassis ground.
>
> Any help is appreciated...
>
> Thanks
>
> MR
...Glad to help,
Scott (delete "nospam." to e-mail)
Scott Holderman
...Glad to help,
Scott (delete "nospam" to e-mail)
Scott Holderman
...Glad to help,
Scott (delete "_nospam" to e-mail)
gfre...@northnet.org
Scott Holderman <aq...@removeme.lafn.org> wrote:
> > 2) Is the shield (if used) connected at the sending or the receiving
> > end of the cable or both?
>
> ...If both ends are balanced, the shield should only be connected at one
> end.
That all depends how long the cable is relative to the wavelength of the
expected RF interference. Leaving the cable shield unterminated at one end
can lead to reflections and standing waves along the length of the shield
which can be introduce more noise than having no shield at all (the shield
becomes an antenna). A rule of thumb is if the cable is longer than 1/20th
the wavelength of the RF interference then both sides need to be grounded.
The drawback here is this will introduce a potential ground loop, this can be
avoided by grounding one end of the shield at RF frequencies through a .01uf
capacitor. The capacitor should be a high frequency ceramic with the leads as
short as is physically possible, the leads can add significant inductance and
defeat the purpose of the capacitor. Film capacitors have inherently higher
inductance and should not be used, a .01uf film cap will start acting like a
inductor well below 10MHz.
Greg
-----------== Posted via Deja News, The Discussion Network ==----------
http://www.dejanews.com/ Search, Read, Discuss, or Start Your Own
Tony
ground return of an unbalanced signal, but far less if all the signals
are balanced. Unless I get a particular problem from it (which I
haven't yet), I ground both ends of the shield over a properly
balanced connection.
Mark De Martini
Mark Rehorst <mreh...@fmi.fujitsu.com> wrote in article
<366801CB...@fmi.fujitsu.com>...
> Can anyone tell me how XLR connectors are used in typical recording
> studio equipment?
> 1) Are they used with an unshielded twisted pair, or with a shielded
> twisted pair (shield over a twisted pair), or with twisted shielded
> pairs (shielded wires twisted together)?
> 2) Is the shield (if used) connected at the sending or the receiving
> end of the cable or both?
> 3) Does the shield connect to the chassis lug or to pin 1 of the XLR
> connector?
1. Generally , twisted pair with an overall shield.
2. If you are telescoping shields to avoid ground loops, it's more common
to tie the shield at the sending end and lift it at the receiving end.
Either way will work, but tying the shield at the sending end has some
advantages for reducing crosstalk.
3. Generally, Pin 1, but, if the chassis of the equipment is solidly
grounded, the chassis lug can be a better place to tie the shield, as this
allows noise & RF currents to flow to ground without going through the
internal ground reference buss of the equipment. AVOID connecting the
shield to both; it's not a good idea to short chassis ground to signal
ground at the XLR connector.
Mark De Martini