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AES EBU & SPDIF

SigmaDSP & SigmaStudio drugoimir Apr 20, 2014 00:00 3 replies Original on forum ↗
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drugoimir Question
Apr 20, 2014 00:00

Hello,

i was just curious if i can just use the spdif I/Os of an ADAU1446 for

direct connection to and from AES/EBU equipment.

For what i've understood, the two formats are quite similiar, with the

exception that AES/EBU contains extra frames for stream labeling,

identification, user data, time stamps and so on.

Saying that i don't need all those extra-features and i want to keep

the component count low, so i will not use a proper

AES/EBU receiver/transmitter chip, what "success rate" can i get

if i use the SPDIF signals directly ? Obviously i'll take care to

be compliant with the electrical specification of the AES/EBU standard.

Until now, i've tried some equipment, a CD player and a PC audio card

both equipped with AES/EBU outputs and they are working like a charm.

Moreover, when working on studio equipment i've always mixed and interconnected

AES/EBU on SPDIF and vice-versa using passive adapters, without any side effect.

But the question arise because on a studio audio processor manual is

stated that "the digital input signal MUST be an AES/EBU standard signal.

This equipment will not work with S/PDIF signals", or something like.

I've not made a test on this unit, but i got its schematic diagrams and it uses

a popular AES/EBU receiver chip which is able to decode also S/PDIF.

I've found another equipment using the same chip, i connected an S/PDIF

to that unit and voilà: pure music out of the box.

So, this is the reason of my doubts: who engineered the first unit did, with

pedantry, stop everything if the receiver chip reports a non-AES/EBU stream?

I repeat, i cannot make tests on that unit, maybe it works flawlessly

on SPDIF as well.

Summarizing: until now i've carelessly, except for electrical matching, interconnected

AES/EBU on SPDIF and vice-versa and i never had problems, never had to say

"oh no! it was not working because i wrongly connected AES EBU to SPDIF", never.

Was it only a matter of luck, or, to avoid using an AES/EBU rtx chip, can i

directly connect the ADAU1446 SPDIF out on AES/EBU inputs on most cases?

Thanks

Tom

Audio Signal Processors

adau1446

s/pdif

aes/ebu

SigmaDSP Audio Processors

ColemanR Reply
Apr 21, 2014 00:00

Hi Ton,

If you are using the correct impedance matching, you should have no electrical issues with operation of the circuit. I would recommend that you use a transformer from Scientific Conversion to create the differential signal from the single-ended, and vice versa:

http://www.scientificonversion.com/catalog.html

Also, please be aware of an anomaly with the S/PDIF transmitter in the ADAU144x family:

http://www.analog.com/static/imported-files/data_sheets/ADAU1442_1445_1446_Anomaly.pdf

Best regards,

Coleman

drugoimir Reply
Apr 21, 2014 00:00

Hello Coleman,

thanks for your answer.

I'll obviously use a transformer to comply to the aes/ebu requirements,

but my question was centered more on the aes/ebu - spdif interoperability.

The anomaly you pointed out is indeed an interesting detail.

So it seems i'm obliged to use, at least, an aes-ebu transmitter.

Thanks

Tom

EZAdministrator Reply
Aug 2, 2018 00:00

This question has been assumed as answered either offline via email or with a multi-part answer. This question has now been closed out. If you have an inquiry related to this topic please post a new question in the applicable product forum.

Thank you,
EZ Admin