Mis-wiring AES/EBU cables; what would happen?
ThBarr
What is the correct pin wiring for AES/EBU cables with XLRs on one end and TRS
jacks on the other and what happens if you wire them incorrectly?
Thanks!
David Josephson
>What is the correct pin wiring for AES/EBU cables with XLRs on one end and TRS
>jacks on the other and what happens if you wire them incorrectly?
I don't know of any device carrying digital audio on a TRS (1/4" phone
plug) connector -- are you sure this is what it is? AES/EBU, now AES-3,
is on XLRs or (unbalanced with a transformer) on BNC.
--
David Josephson / Josephson Engineering / San Jose CA / da...@josephson.com
Philippe J.BOUCHON
> I was wondering if someone could help me with the following question:
TRS
> jacks on the other and what happens if you wire them incorrectly?
Hello,
I am not sure that 1/4" jacks are allowed as 110 Ohms AES-3 connectors.
Anyway, connect your jack as usual for an analog link :
- XLR pin 1 (shield)
- XLR pin 2 (+) --> tip
- XLR pin 3 (-) --> ring
If (+) and (-) wires are swapped, the AES-3 link will still work fine
(bi-phase signal)
Hope this will help.
Philippe J. BOUCHON
E-mail : pbou...@csi.com
http://audio-pjb.com
ICQ# 31354385
Mike Rivers
> What is the correct pin wiring for AES/EBU cables with XLRs on one end and TRS
> jacks on the other and what happens if you wire them incorrectly?
AES/EBU isn't supposed to use TRS connectors, but they work. There are
a couple of patchbays sold for the purpose of patching AES/EBU signals
which use 1/4" long frame jacks, though they usually aren't the
"prewired" kind with jacks in the front and back.
AES/EBU Is a transformer balanced interface with the signal between pins
2 and 3 and the shield on pin 1. The convention when making up an
XLR-to-TRS cable that's not wired to take care of a unique problem is to
connect pin 2 to the tip, pin 3 to the ring, and pin 1 to the sleeve.
I don't know if anyone's done any studies on the theoretical or audible
effect of swapping the polarity of the signal leads on an AES-EBU
interface. I don't expect it to invert the signal polarity by the time
it gets back to audio, but it might affect timing (phase) between
multiple AES/EBU channels.
--
Mike Rivers (I'm really mri...@d-and-d.com)
ThBarr
thbarr
Dean Brewer
> > What is the correct pin wiring for AES/EBU cables with XLRs on one end
and TRS
> > jacks on the other and what happens if you wire them incorrectly?
I asked the same question regarding a Creative CD-ROM digital output which
only had two outputs which seemed even more confusing, so I asked the local
Creative tech boffins and they said there was no polarity, connect them how
you like ? I connected them onto Pins 1 and 2 on the XLR and either way
made no difference. The *only* slightly strange thing I noticed though was
everytime you skipped a track it would lose wordclock sync and then take a
few seconds to lock back on and by then you had missed the start of the
track ?
Regards
Dean
PS - Mike you wouldn't know of anyone who uses a Roland DM-800 / DIF-800
combination would you ? I am battling to find any resources on the net or
any documentation regarding the machines Connectivity to my Yamaha 03D via a
TDIF YGDAI card ? I Picked one up ridiculously cheap from work and really
want to get it working.
Thanks in anticipation
Mike Rivers
> I asked the same question regarding a Creative CD-ROM digital output which
> only had two outputs which seemed even more confusing, so I asked the local
> Creative tech boffins and they said there was no polarity, connect them how
> you like ? I connected them onto Pins 1 and 2 on the XLR and either way
> made no difference.
That's surprising. I didn't know they were cheating on AES/EBU XLR
inputs now. Those are supposed to be balanced between pins 2 and 3.
Unless you tied Pin 3 to ground (pin 1) I wouldn't have expected it to
work at all, though at the high frequency of the digital signal, there
might have been enough capacitive coupling to get the signal through
anyway.
Though I didn't discuss digital connections, I just wrote an article for
Recording on Pin 2 Hot. There are lots of confusing possibilities. I
KNOW that when that article comes out they're going to get a bunch of
letters from readers writing "I connected it up another way and it
worked fine".
> The *only* slightly strange thing I noticed though was
> everytime you skipped a track it would lose wordclock sync and then take a
> few seconds to lock back on and by then you had missed the start of the
> track ?
I would expect this since the input's word clock got confused when it
was interrupted momentarily.
David Rick
>(ThBarr) writes:
>
>>What is the correct pin wiring for AES/EBU cables with XLRs on one end and
TRS
>>jacks on the other and what happens if you wire them incorrectly?
>
>I don't know of any device carrying digital audio on a TRS (1/4" phone
>plug) connector -- are you sure this is what it is? AES/EBU, now AES-3,
>is on XLRs or (unbalanced with a transformer) on BNC.
I have an AdB digital I/O card for my computer that requires cables like
this.
There's no real problem in practice, provided you use 110 ohm cable to
begin with. Wire it like a conventional analog cable (1=shield,2=tip,
3=ring)
in case someone uses it for something else in the heat of battle. But for
digital it doesn't matter (um) a bit. The encoding is in the transitions,
not
the absolute phase.
David L. Rick
Seventh String Recording
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dr...@hach.com