What's the truth about the sync chain?

[mtoy]

Playing with multiple interfaces and devices has led me to wonder what the correct answer to these questions is.

How long can the sync chain be?
How long can a cable in the sync chain be?
Can the sync chain run backwards (from hightest numbered interface to lowest), or sideways through the interfaces, and if no, why not?

[mtoy]

Do I have to offer a prize to the first correct answer

-Michael

[Peter Steinbach]

I'm not sure I understand your meaning of the term "sync". Do you mean video, smpte, etc? A descrition of your setup would help.

[Nick Batzdorf]

Maximum lengths, conventional wisdom:

Superclock (Digidesign 256x word clock): a few feet (5-6), the shorter the better. I don't know whether each Audio Interface regenerates the signal, but I assume so;

word clock (75 Ohm cable): about 20 feet;

digital black (or regular digital audio) AES/EBU (100 Ohm able) or S/PDIF (75 Ohm "video dubbing" cable): around the block.

The order doesn't make any difference other than the cable length. Was that the question? Do I win the prize for first wrong answer?

[This message has been edited by Nick Batzdorf (edited 10-19-99).]

[mtoy]

I hereby award you the Outstanding Orange of Magnificence for Sync Knowledge above and beyond the Call of Duty. You may now refer to yourself in this forum as "Sir Batzdorf"

Thanks.

[Borgbilly]

Good answer Nick, except the SuperClock - 5 or 6 feet and nothing is going to clock. I've been round and round with this one and according to Digi telephone tech support the maximum SuperClock cable length is 18".

Here's the million dollar question: Is there any type of distribution amp for setting up a 'star' or central point distribution of Word Clock signals? I'm starting to run into problems trying to daisy chain to three or more devices.

------------------
Richards Outpost Audio
* Ain't Life Grand?*

[nkf]

Borgbilly wrote:
>>>Is there any type of distribution amp for setting up a 'star' or central point distribution of Word Clock signals? I'm starting to run into problems trying to daisy
chain to three or more devices.<<<

In my studio I use a WC distribution amp
from Lake-People (http://www.lake-people.de/)
since years for my digital setup, although
PT is clocked via AES/EBU. Works flawless.
Their current model is WCD F63 (I have F64).
It is not a SuperClock device.

Nirto Karsten Fischer

[Nick Batzdorf]

Borgbilly, I suspect that the Superclock cable length has to do with what's generating it. You're probably talking about connecting interfaces - which is what the original question was - and I'm spouting theoretical rhetoric.

Well, sort of. I have an MTP AV near the bottom of a 20-space rack and an 888 at the top, and the thing locks fine going through 6' of Radio Shack video dubbing cable.

(Not that I practice what I preach, of course. I'm using a different box to generate word clock and Superclock; the MTP AV is only being used as a MIDI interface.)

[Nick Batzdorf]

Oh, and Aardvark's SyncDA (used to be $850, and I assume it still is) generates six word clock and Superclock outputs from a single digital black or word clock input.