Topic: Converter - 4 x SPDIF to 1 x ADAT?

[fotoralf.be]

Is there anything simple that will accept four stereo SPDIF signals and output them as an eight-channel ADAT signal?

Ralf

[H₂O]

Looks like this may work:
http://www.rme-audio.de/en_products_adi_192_dd.php
 
 

[fotoralf.be]

It definitely won't. The description clearly says it has just one SPDIF input.

Ralf

[H₂O]

It says it has 4 AES/EBU inputs that are SPDIF compatible though - I would think you could get a simple adapter to convert these to SPDIF ins.

[fotoralf.be]

Me stupid. I'll have a closer look at it, then.

Ralf

[DSatz]

No, this will not and cannot work unless the receiving device uses asynchonous sampling rate converters on its inputs. I've never seen a piece of consumer gear with this capability.

The four devices producing the S/P-DIF signals can't be assumed to be synched to the same master clock. As a result, the 8-channel receiving interface would get four different clocks, each of which is at a slightly different frequency and in random phase relationship to all the others. There's no way to synch and interleave those signals into an ADAT data stream, unless (as I said) they can be converted to a common clock--and that would be a rather expensive bit of signal processing if it's to be done well by modern standards.

So basically, no. You might find the inverse--an ADAT-driven device that produces four S/P-DIF output streams, but probably not the configuration you're looking for.

--best regards

[H₂O]

The unit says it has built in Sample Rate convertors (for existing digital signals) - would it still not work?
 
From the RME website:
Features:

• 8-Channel sample rate conversion up to 192 kHz  Sample Rate Conversion can be selected for AES, TDIF or ADAT  8-Channel Sample Rate Conversion without phase errors (sub-sample synchronous)

 
Applications include: 

• 8-Channel AES, TDIF and ADAT input and output for digital mixers with ADAT/TDIF port

[DSatz]

Yes, that sounds like what this type of hookup would require (of course you would need to use AES/EBU inputs as S/P-DIF inputs, but the Web site says that they're designed for such use). And RME equipment is generally quite good. So to my surprise, there appears to be a solution after all. Times have changed!

--best regards

[Reticuli]

I have a need for a 1 x ADAT input to 4 x SPDIF outputs converter.  Seems like it would be cheap.  SPDIF outputs are cheap, though inputs are not, especially implimenting multiple inputs.  ADAT is 8 channels mono PCM each.  SPDIF is stereo PCM.  You put an ADAT in, 4 SPDIF outs, and a properly programmed DSP between the two.  Anyone know of one?  Seems like from my googling of this there's quite a market for one.

[mbgrace]

The RME ADI-4 DD does this.  I use it regularly and it is solid. 
This unit has no sample rate conversion so if using multichannel AES or SPDF inputs they must all be synchronous.  RME is well engineered stuff.
Note that this unit has AES3 connections so you will need to adapt to SPDIF with a cable and possible attenuators.
Rane has a very nice app note on AES>SPDF conversions:
http://www.rane.com/note149.html
Cheers,
Michael

[RichT]

I've just sold my RME ADI-8DD (older version of ADI-192DD) for about £300 ($500). It's almost exactly the same spec (has SRC, which the ADI-4DD doesn't) but "only" copes with sample rates up to 96kHz.
Was a good bit of kit- I just found I wasn't using it. Would be a much cheaper option second hand

http://www.rme-audio.de/old/en/adi/adi8dd.htm