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Gear / Technical Help => Cables => Topic started by: waltmon on March 21, 2006, 04:44:40 PM
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Is there an obvious difference runninng aes instead of spdif? I know aes is the pro input, but is it just hotter levels, or what? Asking because I'm about to have an aes/ebu right angle XLR on both ends made up, and deciding it's worth the trouble.
thanks
Walt in VA Beach
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there is no audible difference, a bit is a bit, however S/PDIF is far less reliable than AES (S/PDIF is more prone to jitter/signal drop)
-bsk
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worth my time...thanks!
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I don't know this for a fact but back when I had my DMIC 20 I was told that you could also have much longer cable runs with AES.
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I'm a bit behind on my reading... ;D
It's not simply a "bit is a bit". There is a lot more that is different, starting with the signal itself. The AES/EBU signal is a 110 ohm signal, which can be run over 100 meters when using the AES/EBU XLR cable -- there is a coax version too, which can be run over lengths much higher (1000 meters?). The SPDIF signal is 75 ohms and comes in two falvors optical (TOS) and coax (RCA connectors). These signals are framed differently, so you can't just plug one into the the other. However, what I've found is that so long as you convert the impedance from 110 ohms to 75 ohms, you're pretty much home free, because the framing issue takes care of itself.
The caveat for all the conversion is going from AES to SPDIF. The DEVA uses AES and so when folks want a digital signal out from me, it's not always clean. What I mean is, sometimes the SPDIF device doesn't like the converted signal, in many cases the odd frames and extra data on the AES signal is interpreted as a copyprotected signal and so the SPDIF device won't allow the converted signal to be used. I have found the only way around this is to use an analog signal instead.
How to convert the signal
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The easiest way to convert the signal is through inline impedance signal converters. The best one's I've found are made by Canare.
http://www.canare.com/index.cfm?objectid=DCBBA8D3-3048-7098-AF5E76E3D1E1CA3D&print=yes
There are other vendors as well, but I really like the Canare versions. You'll have to buy a coax to RCA adapter to use these too, but those are cheap and easy to find.
Wayne
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I'm a bit behind on my reading... ;D
It's not simply a "bit is a bit". There is a lot more that is different, starting with the signal itself. The AES/EBU signal is a 110 ohm signal, which can be run over 100 meters when using the AES/EBU XLR cable -- there is a coax version too, which can be run over lengths much higher (1000 meters?). The SPDIF signal is 75 ohms and comes in two falvors optical (TOS) and coax (RCA connectors). These signals are framed differently, so you can't just plug one into the the other. However, what I've found is that so long as you convert the impedance from 110 ohms to 75 ohms, you're pretty much home free, because the framing issue takes care of itself.
The caveat for all the conversion is going from AES to SPDIF. The DEVA uses AES and so when folks want a digital signal out from me, it's not always clean. What I mean is, sometimes the SPDIF device doesn't like the converted signal, in many cases the odd frames and extra data on the AES signal is interpreted as a copyprotected signal and so the SPDIF device won't allow the converted signal to be used. I have found the only way around this is to use an analog signal instead.
How to convert the signal
-----------------------------------
The easiest way to convert the signal is through inline impedance signal converters. The best one's I've found are made by Canare.
http://www.canare.com/index.cfm?objectid=DCBBA8D3-3048-7098-AF5E76E3D1E1CA3D&print=yes
There are other vendors as well, but I really like the Canare versions. You'll have to buy a coax to RCA adapter to use these too, but those are cheap and easy to find.
Wayne
+t for a good description, and THANKS for the link...I've been looking for some of demz.