• Data
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  • From: Germany
  • Registered: 2021-04-13
  • Posts: 56

Topic: Internal clock question

Hello, this is my first post in this forum. I am a very happy user of the ADI-2 DAC FS since 1.5 years. It's among my two favorite electronic devices (the other one being my iPad Pro 12.9).

Anyway, here's my question. I understand that the unit contains a very good internal clock that is used for USB input. Why can this clock not be used for SPDIF input (I use optical)? I am pretty sure that the clock in my source is not as good as the one in the RME.

UCX II, Quadmic II, ADI-2 DAC FS
Follow me on YouTube: https://www.youtube.com/@thedilettantepianist
  • vinark
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  • Registered: 2009-06-05
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Re: Internal clock question

That is just not how digital works, an external source with internal clock, but rest assured because of steadyclock FS, the external clock is made jitter free so it is just as good as internal. So really don\t worry!

Vincent, Amsterdam
https://soundcloud.com/thesecretworld
BFpro fs, 2X HDSP9652 ADI-8AE, 2X HDSP9632
  • Registered: 2021-12-24
  • Posts: 42

Re: Internal clock question

Do you mean that samples from SPDIF input will be chronically rearranged (reclocked) by the internal clock of the DAC?

  • From: Switzerland, Zürich
  • Registered: 2013-02-20
  • Posts: 191

Re: Internal clock question

no nothing is rearranged.

The SPDIF Clock is the master. The internal clock will be phase (and freuqecy) locked to SPDIF by a clever circuit in the RME device. Actually it removes the jitter from the external clock. As far as I remember there are som quiet deep explanations from RME how it works.

If you want to use the precise internal clock of RME, just feed the RME via USB.

  • vinark
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Re: Internal clock question

The whole advantage of FS tech is that even if you feed it a not so good clock, the ADI will still have no jitter. Have a look at audiosience reviews

Vincent, Amsterdam
https://soundcloud.com/thesecretworld
BFpro fs, 2X HDSP9652 ADI-8AE, 2X HDSP9632
  • ramses
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  • Registered: 2012-10-14
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Re: Internal clock question

Vinark, I think you mixed "SteadyClock" / "SteadyClock FS" with FS.
SteadyClock is the name of the technology.

MC also provided some videos weeks ago, you find them in my blog article.
https://www.tonstudio-forum.de/blog/ind … ses-EN-DE/

As you say, SteadyClock FS can lock even to a very jittered signal, that you would usually not even see in real life use cases.
And it reduces the noise floor significantly, also being demonstrated in the video.

SteadClock takes care of any incoming / used clock signal, refreshes it and the final D/A conversion will be performed with the ADI-2 DAC/Pro's own FS clock.

Yes right, he has not to worry about anything wink

BR Ramses - UFX III, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1680v4, Win10Pro22H2, Cub13
  • Data
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  • From: Germany
  • Registered: 2021-04-13
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Re: Internal clock question

Thanks ramses for the link with the excellent writeup, including the video of MC on SteadyClock / SteadyClock FS. Very interesting explanation of the forms of jitter (interface / internal), and very impressive demonstration esp. of the SteadyClock FS. So basically all forms of input receive the similar clock treatment and end up essentially jitter-free. Excellent!

UCX II, Quadmic II, ADI-2 DAC FS
Follow me on YouTube: https://www.youtube.com/@thedilettantepianist

8 Reply by KaiS (edited by KaiS 2021-12-29 00:50:41)

  • KaiS
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  • Registered: 2020-02-05
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Re: Internal clock question

IdleTalk wrote:

Do you mean that samples from SPDIF input will be chronically rearranged (reclocked) by the internal clock of the DAC?

Rearranged isn‘t the correct word, .

The samples are precisely aligned by “Steady Clock FS“ before handed to the DAC chip.
This way misalignment, read jitter, is effectively removed, as confirmed i.e. by Audiosciencereview.

https://www.audiosciencereview.com/foru … iew.13379/

https://www.audiosciencereview.com/forum/index.php?attachments/rme-adi-2-dac-fs-version-2-usb-jitter-audio-measurements-png.63557/

Since then “Steady Clock FS“ has been improved even further by updatable firmware, so all existing units benefit.


Conclusion:
Jitter is a non-isue for ADI-2, no matter what quality the source clock has, any extra external jitter-removers are obsolete and waste of money.

KaiS's Website