• BatM
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  • Registered: 2014-08-25
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Topic: SPDIF lock

When using the UCX as a tool to test SPDIF transfer, I want to better understand how the PLL lock and the LED signal on the front panel function.

I've observed that when I connect optical or coaxial in a loopback, the SPDIF and/or ADAT LED remains solid. In this setup, DeltaWave consistently measures a bit-perfect result of 99.96% through the physical loopback.

However, when testing with different SPDIF sources, including CD players as DUT, the LED blinks 2-3 times at roughly 2-second intervals. The recordings sound fine, and DeltaWave results show good average clock drift but rarly better than 20% bit accuracy. Upon closer inspection, there are occasional periods of drift, but not at the same 2-second intervals.

Is this expected behavior? Or are there settings where I can set the sample rate and clock source to help mitigate the blinking LED? I’ve tried Fireface ASIO with Cubase and WASAPI with DeltaWave/Adacity

tia

2 Reply by vinark (edited by vinark 2024-10-03 21:54:24)

  • vinark
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Re: SPDIF lock

In the settings clock source should be set to coaxial or optical, whatever you are using. The sync status must be a permanent sync, not changing to lock
Oh and loopback works because of course the device is in sync with itself.  With a loopback the clock must be internal to prevent a clock loopback situation.

Vincent, Amsterdam
https://soundcloud.com/thesecretworld
BFpro fs, 2X HDSP9652 ADI-8AE, 2X HDSP9632
  • BatM
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Re: SPDIF lock

Thanks, but I cant for the life of me figure out where to set what interface to synk to. I'm guessing the blinking actually might not be due to missing sync, but rather the autodetect are probing for other sourches?

To stress test I recorded both optical and coax simultaneous using a CD player as sourche and both LEDs blinket at the same time. Result wont pass a nulltest and DeltaWave register jitter of 12ns between the two files so I would be curious as to which interface the sync is prioritising in a usercase like this.

  • vinark
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Re: SPDIF lock

On your computer there is an app with the ucx settings ln windows it is in the systray.
And the blinking means not in sync.
Probably read the manual. I have no ucx so maybe it is possible from the device, maybe you need the setting app.

Vincent, Amsterdam
https://soundcloud.com/thesecretworld
BFpro fs, 2X HDSP9652 ADI-8AE, 2X HDSP9632
  • BatM
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Re: SPDIF lock

Thanks! System tray where the solution where hiding. Never touch these settings all the time I've had the UCX.

To my ex use the laptop I'm currently working from have a defective screen hiding everything 5 cm on the right side in colorful lines. Including systray wink

Thanks!

  • vinark
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Re: SPDIF lock

Ah great!

Vincent, Amsterdam
https://soundcloud.com/thesecretworld
BFpro fs, 2X HDSP9652 ADI-8AE, 2X HDSP9632