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Wiring Cat-5 for Digital AES Connection
Old 4th October 2007
  #1
Here for the gear
 
🎧 10 years
Wiring Cat-5 for Digital AES Connection

As this seems to work and many people are using this nowadays. I would like to know how to wire a RJ45 Cat-5 to a XLR connector. I am also planing to use a regular ethernet patchbay to have all my digital Ins and outs.
Old 4th October 2007
  #2
Gear Maniac
 
🎧 15 years
Hello,
Yes, this is common these days. Using an ethernet patch bay you can send 8 channels/4 pairs over each cat 5. Just don't feed it through a switch! I've included a pinout.

Any questions let me know.

H
Attached Files
File Type: pdf rj45 aes pinout.pdf (14.5 KB, 5438 views)
Old 4th October 2007 | Show parent
  #3
Here for the gear
 
🎧 10 years
thanks a lot !!!!! So, this is really safe?I mean, theis is really better than doing and there Should I use Cat-5e or Cat-6 standard instead or regular Cat-5 will do it?
Old 5th October 2007 | Show parent
  #4
Gear Maniac
 
🎧 15 years
Hello,
Safe? Sure!
Couple of points - Cat5/6 has the same characteristic impedance as balanced AES, and shielding is not necessary - ethernet is not shielded.
The TX and RX of a balanced AES stream is transformer balanced and floating.
Cat5e or 6 is not an issue, but not for the reason you'd expect - the bandwidth of AES is a hair under 2 MHz, nowhere near the 50MHz of Cat5 or the 500MHz of Cat6. That said, AES receivers are not as good at reclocking rounded signals, so you're better off with Cat6 in theory. However, Cat5e works very well and it's cheap.
If you're sending the signals a distance you're always better with 75ohm coax AES, but if you're just shipping it around locally then Cat5e will work great. It's NOT a compromise at all.

H
Old 5th October 2007 | Show parent
  #5
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gurubuzz's Avatar
 
1 Review written
🎧 15 years
When you mean locally what do you consider locally?

Less than 50 feet?

Less than 100 feet?
Old 5th October 2007 | Show parent
  #6
Gear Maniac
 
🎧 15 years
Hello,
There's no hard and fast rule on that. 200 feet on Cat5e should be no problem as long as you're not going through too many patch bays on the way - connectors and the reflections they cause are the primary issues. Keep the pairs at the proper twist, don't kink them too much, and use real ethernet, proper impedance, 4pair patch bays. If you're using normal mic cable you're lucky to get 100 feet.
Ethernet and coax AES have vastly improved reclocking circuits - in theory if balanced AES reclockers were as good as ethernet ones you could ship the signal 1.5 miles, but not any chance at all of that happening!
H
Old 5th October 2007 | Show parent
  #7
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crypticglobe's Avatar
 
2 Reviews written
🎧 15 years
Guys! It works... sure... but sounds BAD!. I know, It's digital... shouldn't matter. But when I first hooked it up (professional cable builder here), it didn't sound right to me. I wired up the exact same length with mogami digital AES cable... WHOA!!!! I was really bummed cuz it drove me cable cost WAY up.... but... it was just way too obvious...

HUGE difference in sound quality. HUGE!! I will never use CAT-5 again.

I know... the arguments will come... like..."it's zeros and ones, it HAS to be the same". I know, I used to say the same thing.... but my ears don't lie. Try it.....

Just a word to the wise....
Old 7th October 2007 | Show parent
  #8
Gear Maniac
 
🎧 15 years
Hello Steve,
Good to see you here on the GS forums.
My experience has not been at all like yours - we even did tests (because it IS ones and zeros, so we had to be sure) and it was flawless - EXACT same sound and EXACT same data came through.
I know you're good so I respectfully suggest there may have been another variable.
H
Old 7th October 2007 | Show parent
  #9
Gear Guru
 
kafka's Avatar
 
🎧 15 years
Quote:
Originally Posted by crypticglobe ➑️
Guys! It works... sure... but sounds BAD!. I know, It's digital... shouldn't matter. But when I first hooked it up (professional cable builder here), it didn't sound right to me. I wired up the exact same length with mogami digital AES cable... WHOA!!!! I was really bummed cuz it drove me cable cost WAY up.... but... it was just way too obvious...

HUGE difference in sound quality. HUGE!! I will never use CAT-5 again.

I know... the arguments will come... like..."it's zeros and ones, it HAS to be the same". I know, I used to say the same thing.... but my ears don't lie. Try it.....
Well, it only HAS to be the same if you get all of the ones and zeros. If you notice a difference, you're losing some. Try crimping another set and see if it improves anything.
Old 9th October 2007 | Show parent
  #10
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gurubuzz's Avatar
 
1 Review written
🎧 15 years
Well,

I'm going to try it ... I've got ship loads of cat 5

I'm going to do a Cubase system link.... "what's that??", ask all the plethora of perplexed Protools professionals ...

Old 22nd June 2015
  #11
Gear Nut
 
🎧 5 years
I am curious what kind of distances, and at what sample rates, people are successfully using Cat5/5e/6 cables to run AES/EBU? And what kind of latency increase or buffer size increase have you experienced in moving to longer runs?

I want my machine room back for tape machines so the digital stuff needs to move further away (150'). Most tracking is done at 192kHz. Before I make the move I want to hear what others are experiencing with Cat5/5e/6 cable runs at 192kHz.
Old 4th July 2015
  #12
Gear Nut
 
🎧 5 years
Bump, before I spend a few hours doing this.... Anyone?
Old 4th July 2015
  #13
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Cozmik Prod.'s Avatar
 
🎧 5 years
Make one really long cable and test it for yourself maybe ?
Old 24th August 2015 | Show parent
  #14
Here for the gear
 
🎧 10 years
Quote:
Originally Posted by crypticglobe ➑️
Guys! It works... sure... but sounds BAD!. I know, It's digital... shouldn't matter. But when I first hooked it up (professional cable builder here), it didn't sound right to me. I wired up the exact same length with mogami digital AES cable... WHOA!!!! I was really bummed cuz it drove me cable cost WAY up.... but... it was just way too obvious...

HUGE difference in sound quality. HUGE!! I will never use CAT-5 again.

I know... the arguments will come... like..."it's zeros and ones, it HAS to be the same". I know, I used to say the same thing.... but my ears don't lie. Try it.....

Just a word to the wise....
And now a word from the other professional (me):

I work in broadcast, I specialise in systems design in both the video and audio realms. I can safely say that CAT5 works fine. Bits are bits and as someone already argued before, if it sounds any different, it means you're losing bits. If you think CAT5 is bad for AES, we would make your head spin at the Olympics, where in the past, AES was passed over 20m of unshielded CAT5 without issue and 50m of shielded CAT5 but that was way way back in the day. Not even a glitch, pop or click, carrying 48kHz/24bit.

In recent times, we use CAT6 and out of desperation, I have had 100m runs in CAT6, carrying 192kHz/24bit and again with no issues to air at any point. I say desperation though because typically, I make it a rule to use coax cable for anything over 50m for reasons already explained by other posters here about balanced vs unbalanced cables.

If you have a fancy AES analyser, such as a Neutrik Digilyser or CTP Systems dBbox II, you can actually monitor the data and I'm sure you'll find you're dropping bits. What brand CAT5 cable was it? How old was that cable? Given you're using CAT5 and not even 5e, which is barely worth purchasing against the cost of CAT6 these days, I'd dare say that the cable is just way too old and probably sufficiently oxidised to cause you grief.

But in all honesty, if you're going for 150ft and you want multiple balanced AES feeds in a single cable snake, I'd strongly suggest you either use multi-core AES cabling made for the task by someone reputable but not with a "Monster Cable" price tag, be it from Belden, Canare, Draka or Canford, or alternatively, if you don't mind going unbalanced, use something like Belden 1855A or an equivalent. There are multi-core snake versions with this type of cable within as well, for neatness sake. I'd be aiming for unbalanced cables at that length, personally, unless your gear only accepts balanced connections and using transformers would be expensive and cumbersome for you.

If you must use data cabling, I suggest you aim for shielded CAT6 and ground the shield at both ends to play it safe. While that is the general rule, where a ground loop is present, one breaks the rule by shielding the cable only at one end and while it shouldn't work in theory, it does in practice on those rare occasions. I've seen it before and we've either had to have the equipment all plugged into the same circuit in a cabin out at a venue or we otherwise isolate the AES cable's grounding from each other. Got to love digital voodoo.

Last edited by Artstar; 24th August 2015 at 04:45 PM.. Reason: Finer detail
Old 21st April 2016
  #15
Here for the gear
 
🎧 5 years
Greetings my friends!
I've just bought PMC twotwo5 and want to connect them with RJ45 cable. Bud I didn't have it in the box. Please tell me, can I use regular network-cable for connection between them or I must make something special? Maybe crossover?
Old 22nd April 2016 | Show parent
  #16
Here for the gear
 
🎧 10 years
Quote:
Originally Posted by djkot ➑️
Greetings my friends!
I've just bought PMC twotwo5 and want to connect them with RJ45 cable. Bud I didn't have it in the box. Please tell me, can I use regular network-cable for connection between them or I must make something special? Maybe crossover?
Nice choice of monitors. As for the cable, while it's not impossible for a manufacturer to use odd pinouts for their AES distribution (AEQ being an example of supposedly "professional" audio product doing just that), provided there is no change of those pinouts between the IN and THRU connectors, then there shouldn't be any need for crossover cables and whatnot.

I can't find anything in their manuals or datasheets about the pinouts, so I can say definitively what the answer is but I can predict that it's likely to be fine with a regular networking cable.

The signals themselves are very low level in both voltage and current so that even if you did end up shorting them to ground, you wouldn't blow anything up. Just plug in a regular network cable and if it's stable, great. If it's not stable or doesn't work at all, then you know you need something different. In which case, contact PMC's support.
Old 22nd April 2016
  #17
Lives for gear
 
🎧 15 years
It might boil down to what / how good Cat5 - Cat5e - Cat 6 cable you actually use. AES audio needs to see 110 ohm impedance otherwise you can have clocking problems due to signal reflection. Cat5 - Cat5e - Cat 6 is 100 ohms with a +/- 15% margin. This means that Cat cable could be 85 ohms up to 115 ohms impedance (if it's in spec). Maybe one guy gets lucky and uses some Cat cable that's close to 110 ohms or the gear it's connected to isn't as picky with impedance or reflected signal. Maybe the next guy has a different set of variables. This could account for the two completely different users experiences reported in this thread.
Old 22nd April 2016
  #18
Here for the gear
 
🎧 10 years
Such 15% mismatches in those impedances aren't such a big issue when you're dealing with lengths of less than 30m, in my experience. You'd be surprised how much AES audio is transported along unshielded CAT5e or CAT6 in broadcast facilities. Thankfully not as much as the proper AES shielded twisted pair multicore cables but still a fair amount all the same and they get away with it, thanks in part to the robust nature of AES.

In the case of a stereo pair of speakers, I can't imagine our guy here would be looking at using that long a cable in the first place but that is a wild guess on my part.
Old 22nd April 2016 | Show parent
  #19
Here for the gear
 
🎧 5 years
Quote:
Originally Posted by Artstar ➑️
Nice choice of monitors. As for the cable, while it's not impossible for a manufacturer to use odd pinouts for their AES distribution (AEQ being an example of supposedly "professional" audio product doing just that), provided there is no change of those pinouts between the IN and THRU connectors, then there shouldn't be any need for crossover cables and whatnot.

I can't find anything in their manuals or datasheets about the pinouts, so I can say definitively what the answer is but I can predict that it's likely to be fine with a regular networking cable.

The signals themselves are very low level in both voltage and current so that even if you did end up shorting them to ground, you wouldn't blow anything up. Just plug in a regular network cable and if it's stable, great. If it's not stable or doesn't work at all, then you know you need something different. In which case, contact PMC's support.
Big t hanks for Your answer, will buy it tooday and try. BTW, I wrote PMC support Yesterday but still no answer...
Old 22nd April 2016 | Show parent
  #20
Here for the gear
 
🎧 5 years
Quote:
Originally Posted by Artstar ➑️
Nice choice of monitors. As for the cable, while it's not impossible for a manufacturer to use odd pinouts for their AES distribution (AEQ being an example of supposedly "professional" audio product doing just that), provided there is no change of those pinouts between the IN and THRU connectors, then there shouldn't be any need for crossover cables and whatnot.

I can't find anything in their manuals or datasheets about the pinouts, so I can say definitively what the answer is but I can predict that it's likely to be fine with a regular networking cable.

The signals themselves are very low level in both voltage and current so that even if you did end up shorting them to ground, you wouldn't blow anything up. Just plug in a regular network cable and if it's stable, great. If it's not stable or doesn't work at all, then you know you need something different. In which case, contact PMC's support.
Doesn't work :-(
Old 22nd April 2016
  #21
Here for the gear
 
🎧 10 years
So it is a proprietary cable after all. Oh well, hopefully they can at least give you the pinouts, as I am now curious.
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