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[marcel]

The balanced AES/EBU digital format...

The mix from my desk feeds an AD-824 module in a Lavry 4496 chassis.  I return the digital output of this to a couple of the AES inputs on one of our Rosetta 800s for mixdown to Protools.  However, the desk has no balanced 2-mix inserts, so I prefer to put any 2-mix processing inline between the desk output and the AD.  This is great, except it does not allow for monitoring of the 2-mix processing.  Up until now, I have mixed to a pair of bus outputs in the desk and looped this mix back to the board for monitoring, tying up precious real estate.

I would like to split the AES signal to allow for simultaneous mixdown and monitoring through the Lavry DA-824, which can then be fed back into the desk's alternate 2-mix input.  Push a button to hear 2-mix processing.

Can I just make an AES mult cable, or is it not that simple?  

Thanks.

[ssltech]

Impedance mismatch. You'll present a 55Ω load instead of 110Ω.

An AES distribution amplifier is the only proper way.

Keith

[marcel]

Thanks, Keith.  I'll look into an amp of some sort.

[marcel]

http://www.proaudio.com/product_info.php?cPath=21_22_211& ;products_id=33

Wow.  Not cheap!  Maybe I'll think about some other way of doing this.

[Jay Kadis]

AES splitter transformers (p/n SC945-01) are available from:

http://www.scientificonversion.com/

[marcel]

Thanks, Jay.  

Is it as simple as putting one of those in an enclosure with the proper connectors and cabling?  If so, I may be able to handle a DIY.  If it's any more involved...  Let's just say I'm not exactly an EE.

[Jay Kadis]

marcel wrote on Wed, 15 December 2010 19:33

Thanks, Jay.   Is it as simple as putting one of those in an enclosure with the proper connectors and cabling?  If so, I may be able to handle a DIY.  If it's any more involved...  Let's just say I'm not exactly an EE.

I think that should do it.  From their FAQ:

"10. How can we drive 2 AES/EBU outputs from an AES/EBU source without using active circuitry, e.g. to make an adapter?

Use our SC945-01 "SuperSplitter" to make a passive splitter (only for 110 Ohm balanced applications).

A complete splitter requires the transformer, a resistor and a few connectors, please see the spec sheet.

Optimized over the entire range 32 - 192 kHz! Very low jitter and low aberration.

Only 3 dB loss from input to each output! Far surpasses any other digital audio splitter available!"

[marcel]

Great!

Sounds like something I may be able to handle.

Thanks again, Jay.

[Fletcher]

It might take a while to find one -- but Lucid used to make a brilliant AES/EBU distribution amp for under $600 USD -- Lucid was owned by Symmetrix so that might be an entry point of contact -- or maybe keep an eye peeled on eBay.

Best of luck with the search!!

[Jim Williams]

You can wire up an extra crystal 8416 driver chip, that avoids the -3db insertion loss of the passive transformer split. You will need to solder and have chops.

As to AES, I split from that organization years ago.

[marcel]

Solder, yes.  Chops, definitely not.

Is there any problem with the loss of signal strength if the cable runs are short (<6')?

[ssltech]

It's not the distance, that's not actually relevant in this case, unless of course you plan to use something as poorly conductive as twisted wet string for cable.

AES has an acceptance window, and different AES specs have different minimum voltages. -3dB means you get slightly less than 71% of the voltage that you started with. -If you were comfortably within the window, this will still work. -If not... it might not function.

Personally I always use D/A's, though I know it CAN be done without them. Jim is essentially describing building your own simple D/A.

Straight multing however, is always a no-no.

Keith

[tom eaton]

Every ZSys router will do that for you... you can grab an 8X8 from the eBay world pretty easily usually.

http://cgi.ebay.com/Z-Sys-Digital-Detangler-S-PDIF-AES-Digit al-Audio-Router-/230544707133?pt=LH_DefaultDomain_0&hash =item35ad890e3d

$360

I've owned a couple different models and they have never been an issue.

t

[marcel]

tom eaton wrote on Fri, 17 December 2010 13:46

Every ZSys router will do that for you... you can grab an 8X8 from the eBay world pretty easily usually.  http://cgi.ebay.com/Z-Sys-Digital-Detangler-S-PDIF-AES-Digit  al-Audio-Router-/230544707133?pt=LH_DefaultDomain_0&hash =item35ad890e3d $360 I've owned a couple different models and they have never been an issue. t

Thanks for the tip, Tom.