I have just got an Apogee Trak 2 with a TDIF AMBus card that I'm trying to connect to an Avid/Digidesign 192 Digital via TDIF and I'm experiencing no end of troubles. Everything is clocked correctly with the Trak 2 as master with all of my digi interfaces locking as they should.

The problem is that I can't get any audio out (Headphones and 8ch DAC card) of the Trak 2 apart from the built in oscillator, I'm pretty sure that I have made a novice mistake with the routing inside the Trak 2 so if anyone has any experience with this device and could offer advice I would be very appreciative.

Problem solved!

I have to clock the Trak 2 to the TDIF AMbus card, which in turn is connected to the 192 running on internal sync rather than the Trak 2's internal clock. By doing so everything sprung into life like magic. This is a bit of a shame as I'm pretty sure the clock on the Trak 2 will be better than the 192.

Oh well it's working now, though after reading the manual for the TDIF card for the third time I think there may be a way of running the internal clock which I will try when time permits

You should certainly be able to run the trak 2 on its internal crystal, with the 192 slaving to its TDIF output -- although if it won't lock up to the LCLK in the tdif cable you might need to run wordclock from the trak to the 192 and have it slave to that instead.

The fact that you could get the oscillator out suggests to be an incorrect matrix setting in the trak 2.

However, synchronisation to tdif is notoriously fickle!

H

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Technical Editor, Sound On Sound

Quote Hugh Robjohns:

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You should certainly be able to run the trak 2 on its internal crystal, with the 192 slaving to its TDIF output -- although if it won't lock up to the LCLK in the tdif cable you might need to run wordclock from the trak to the 192 and have it slave to that instead.

The fact that you could get the oscillator out suggests to be an incorrect matrix setting in the trak 2.

However, synchronisation to tdif is notoriously fickle!

H

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Thanks for your input Hugh, it was your review all those years ago that developed my interest in one day owning a Trak 2 when I could actually afford one!

I have all audio passing correctly in and out of the unit as long as its clocked to the 192 via TDIF. As soon as I change the Trak 2 Clock source to internal and 192 to WC the Trak 2s output has regular drop outs.

I have tried to run the WC out of the Trak 2 to the WC in on the 192, set the Trak 2 to internal sync and the 192 to WC sync, but no dice! As far as I can tell this should work as I know the routing is now set up correctly in the Trak 2, the only thing I'm changing is the Clock source and the way in passes between then two devices.

After reading the TDIF ambus card manual I'm wondering if it has something to do with the LRCK master DIP switch

http://support.apogeedigital.com/assets/documentation/ad8000cards_usersgui de.pdf

I have tried it on and off but same result.

Quote ninebynine:

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As soon as I change the Trak 2 Clock source to internal and 192 to WC the Trak 2s output has regular drop outs.

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It will probably be the 192 losing lock and failing to decode the TDIF signal properly, rather than the Trak 2 losing its output. Is there an option on the 192 to slave sync to the TDIF embedded clock?

TDIF is a notoriously fickle interface, and phasing alignment discrepancies between the TDIF data and the external wordclock can cause exactly this kind of problem.

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I have tried to run the WC out of the Trak 2 to the WC in on the 192, set the Trak 2 to internal sync and the 192 to WC sync, but no dice!

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I think it's generally best to use the WC output on the AMBUS card itself, rather than the Trak 2 one.

Is the WC cable particularly long?

H

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Technical Editor, Sound On Sound

Quote Hugh Robjohns:

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Is there an option on the 192 to slave sync to the TDIF embedded clock?
H

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Yes there is but this also causes the same problem.

Quote Hugh Robjohns:

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Is the WC cable particularly long?

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No, it's only 30cm between the two units. I have also tried the WC out on the AMBUS card with the same result.

The unit also has a Digi 8+ AMBUS card installed, so think I'll source a Legacy digilink cable and try connecting the Digi 8+ card to the legacy port on the 192.

BTW, if anyone reads this that has a Legacy digilink cable they want to sell for a reasonable price let me know, I don't fancy paying £50 for one on eBay.

It might be worth checking to see that the wordclock input on the digi192 is properly terminated. If not, then use a BNC T-piece adapter with a 75 ohm termination plug on one end and connect the other to the WC lead from the Apogee. It's unlikely to be the problem, but I have seen things refusing to lock up before becuase the WC wasn't terminated.

However, I suspect this is a clock phase issue with the TDIF input and a 192 that just doesn't like it!

H

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Technical Editor, Sound On Sound

Quote Hugh Robjohns:

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It might be worth checking to see that the wordclock input on the digi192 is properly terminated. If not, then use a BNC T-piece adapter with a 75 ohm termination plug on one end and connect the other to the WC lead from the Apogee. It's unlikely to be the problem, but I have seen things refusing to lock up before becuase the WC wasn't terminated.

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I have also tried that.

As an experiment I also tried connecting the Trak 2 to an old MOTU 2408MKII I have gathering dust and it's behaving exactly the same.

This is the first time I've actually used TDIF to connect thing as I usually use AES/EBU or ADAT so I'm learning now to avoid TDIF at all costs!

Thanks for your help anyway.

It's no wonder that it was never a popular interface format and has been virtually extinct for a decade already...

AES3 and ADAT remain popular interface formats for a reason.

H

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Technical Editor, Sound On Sound