AES EBU & SPDIF
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
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
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
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EZ Admin
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