DA-38 TDIF Transfers with IF-88AE (wordclock?)

Discussion in 'DRTS Multi-channel Recorders' started by thared33, Apr 18, 2017.

  1. thared33

    thared33 New Member

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    I'm confused about something. I have a couple DA-38 machines and a couple IF-88AE TDIF-AES converters. I've got both 38s synced with the normal cable, both are going TDIF to the IF-88AE, and on my Pro Tools interface(s) I've selected to sync to digital wordclock. It seems to work well but I'm confused about TDIF and its wordclock implementation.

    I've read various things like that the DA88 doesn't support wordclock on its TDIF output (but that the 38 does), and also that TDIF doesn't carry wordclock at all so I don't know what to believe. The IF88AE has no wordclock input connector, only output, so I'm guessing that TDIF does in fact carry a wordclock signal and that the 38 is shooting it out via TDIF into the IF88AE. Shouldn't the IF88AE be locking to that wordclock? If so, what the IF88AE shoots out of its AES ports should be that same wordclock, which would get my Pro Tools interface to lock to the incoming AES wordclock.

    PS: I haven't transferred anything from Pro Tools back to the DA-38, but I'm guessing that -IF- everything I said above is correct, the exact setup above would also be fine for transferring from Pro Tools back to the DA-38s. The IF88AE has a wordclock output port, but I don't see why I'd ever need to reverse it and make my 38s the slaves with Pro Tools being the master to transfer back to the 38s.

    The IF88AE manual always shows a wordclock cable from the IF88AE to a DA88 (not 38) when transferring TO the DA88, but never from it. Maybe it's because the 88 can't sync to TDIF wordclock, but again, why would you need to reverse it and have your interface as the master when it's already the slave? Maybe the DA88 is different from the DA38s for some reason in that regard.
    Last edited: Apr 18, 2017
  2. thared33

    thared33 New Member

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    If I knew where the IF-88AE were deriving its wordclock from, this would be easier to figure out.

    http://www.recordingeq.com/tmd1k/1ksec03.htm

    ^^^ at the bottom, it leads me to believe that a DA-38 transmits WC via TDIF and that a DA-88 does not. If that's true, I'm not sure the IF-88AE would even sense WC info from a DA-38 via TDIF since that machine came a few years later. However as mentioned, the diagrams in the IF-88AE manual lead you to think that the IF-88AE can get clock info from a DA-88 via TDIF since there is no WC input on the IF88AE.

    I read a random comment on an old forum that said that the WC output on the IF-88AE is derived from the AES input, but I'm not sure about that.
  3. thared33

    thared33 New Member

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    Turns out, the IF-88AE is sourcing its wordclock from the TDIF port, and what's coming out of its BNC connector is sourced from the AES input. If I go DA-38 -> TDIF to IF-88AE -> AES to audio interface and lock my interface to the AES wordclock, I think that's all that I need for going both to and fro. The DA-38 would be the master and my audio interface would be the slave for everything at all times. Correct me if I'm wrong.

    To stress, the IF-88AE manual shows there needing to be a BNC from the IF-88AE to the DA-88 only when you're transferring to the DA-88, and again it just seems unnecessary if your interface is already slaved to the DA-88. Perhaps it works fine without the BNC on a DA-38, but not with a DA-88 since it has some sort of peculiarity that we don't know about.

    If anyone else would like to chime in, feel free.
  4. RedBus

    RedBus Respected Member

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    The DA-88 can't lock to TDIF input, so it needed the BNC word clock from the IF-88AE.
    DA-38 and later can lock to TDIF. No need to use the BNC.
    thared33 likes this.
  5. thared33

    thared33 New Member

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    You can't select for the 38 to lock to TDIF though. Does that happen automatically when you press the Digital In button? If so, that means I'll have to switch my audio interface into being the master for layback. I was hoping I could set it up like I described and be done with it, without having to switch anything.

    If pressing Digital In does indeed make the 38 sync to incoming TDIF wordclock, I can see it functioning correctly (with my setup) only if the DA-38 is also still generating wordclock and sending it out via TDIF simultaneously as it receives it (on the same TDIF). Essentially that would mean it's syncing to its own clock, it's just making a round trip.

    Correct me if I'm wrong on any of that.
    Last edited: Apr 20, 2017 at 11:08 PM
  6. RedBus

    RedBus Respected Member

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    Yes, If I recall correctly, selecting Digital IN means the DA-30 will lock to TDIF. If you select Digital In and WORD IN, then you're clocking from the BNC.
  7. thared33

    thared33 New Member

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    But here's the thing: when I select digital in and it's clocking to TDIF (which would come from the AES input), is the DA-38 still generating/sending wordclock out the TDIF as well? If the answer is yes, I'm golden. If the answer is no, I'll have to switch my audio interface to be the Master for layback instead of leaving the DA-38 as the master and my audio interface as the slave 100% of the time for everything.
  8. RedBus

    RedBus Respected Member

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    What is the AE88 set to for clock? You've got 3 digital devices, one has to be the clock master.
    DA-38, IF-AE88 or your audio interface?
    If the DA-38 is locking to the IF-AE88 via TDIF in, the IF-AE88 can't lock to the DA-38 TDIF out.
    The manual wasn't clear, but I don't think the DA-38 can be a clock master and still receive digital input, your choice is TDIF (Word OFF) or BNC (Word ON).
    Thus either the IF-AE88 or audio interface needs to be the clock master in this situation.

    Is this something you need to change often?
  9. thared33

    thared33 New Member

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    The IF88AE doesn't have a way to select any clock source at all, it just works out of the box and that's what the confusing thing about it is. I don't think it even generates its own internal clock but I may be mistaken.

    I would like my DA-38 to be the master, and my audio interface the slave 100% of the time so I can go back and forth without having to mess with it. I won't need to change it too often (if I have to), but it would just be nice to not have to touch it is the thing.

    When I have my audio interface as the slave, and I hit Digital In on my DA-38, my audio interface doesn't have any blinking LEDs or any indication that it has lost sync. That's what's leading me to believe that the DA-38 can be a clock master while still receiving digital input. Still unsure though.
  10. RedBus

    RedBus Respected Member

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    Ah, here's the confusing part. the IF-88AE was designed for the DA-88 only. It was replaced with the IF-AE8 and then the IF-AE8HR. I don't think the DA-38 was designed to be used with the IF-88AE.
    I have the manuals for the later two devices, but not the original IF-88AE. I'll have a wider look around after NAB.
    But, none of the devices were designed to have independent input and output clocking.
  11. thared33

    thared33 New Member

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