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Tell me, what is an external clock supposed to do?

 

According to Sound on Sound:

 

"Overall, it should be clear from these tests that employing an external master clock cannot and will not improve the sound quality of a digital audio system. It might change it, and subjectively that change might be preferred, but it won't change things for the better in any technical sense."

Source: http://www.soundonsound.com/techniques/does-your-studio-need-digital-master-clock#top

 

It seems like talk of external clock is the normal audiophilia nonsense.

 

I would be happy to be proven wrong, but can someone refute the conclusion of Sound of Soun technical editor Hugh Robjohns?

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7 minutes ago, julian.david said:

Hi there,

 

Thank you all for the interest in the REF 10. There absolutely is a relevance to getting the REF 10 and using it exclusively as an external reference for the MC-3+USB. Obviously it would be ideal if all the devices in your setup would have a 10 MHz, but we've found a clearly audible improvement in SQ just by using the REF 10 only for the MC-3+USB. In fact, our booth setup at High End was pretty much just that: we had a standard MacBook Pro running Roon and feeding the MC-3+USB with a variety of files (from 44.1 kHz to DSD256). The MC-3+USB was outputting to a Linear D headphone DAC by Lehmann Audio via Toslink (S/P-DIF optical). Then we would switch between internally referenced re-clocking with the MC-3+USB's internal clock and externally referenced re-clocking with the REF10. There was no way to externally sync the DAC unfortunately. But despite the fact that the optical connection to the DAC was a "jittery" optical one, there was a clearly audible improvement in staging, depth, and smoothness of sound when applying the REF 10 reference. 

 

So in a nutshell: yes, it is acceptable to 'slave' just the MC-3+USB :D

 

Hope this helps!

Thanks for interesting answer!

 

It means, that it would be possible to capture/record the sound with and without Ref10, wouldn't it?

 

In that case, you'd be able to present two sound files: One with the Ref10, and another without the Ref10.

 

Then it would be possible to evaluate the "sound" of the Ref10 in the comfort of one's own listening space.

 

Do you see my point?

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1 hour ago, julian.david said:

 

Well, if only it was so simple ;-)

You are still talking about digital files here and the re-clocking does not change the bits of the source material at all. The re-clocking process (at least how we do it) is perfectly bit-transparent. Some other manufacturers do re-clocking by applying a sample rate conversion (SRC), but that's not how MUTEC does it. Clocking and re-clocking is all about the timing between samples and how the DAC is able to convert these samples into analog audio. So unfortunately there is no test (to my knowledge) of the re-clocking we can do by recording the output of the MC-3+USB. This applies for the re-clocking process in general, whether we do it based on the internal clock of the MC-3+USB or based on the REF 10. 

 

Does that help?

 

Julian

 

Well, it should be possible to capture the sound of the Ref10, employing an analog-to-digital converter.

 

You have 3 scenarios to be captured:

 

1) Without the Ref10

2) With the Ref10 connected to MC-3-USB only

3) With the Ref10 connected to the whole chain of MC-3-USB and the AD converter.

 

AD and DA cconverters are extremely transparent these days, cfr. Studio Magazin 10/2016 where different AD converters were tested and test files were made:

 

http://accelerando.audio/de/studio-magazin/

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13 minutes ago, julian.david said:

 

Hi there,

 

The link you posted unfortunately is in German (which a lot of people don't speak here) and it doesn't give any information about what the audio files represent, what exactly was tested, and how. So I'm not sure what to make of that. 

 

But regardless, we are talking about detailed, yet significant improvements on a high-end level here. The test you are suggesting introduces a host of variables, a relatively elaborate, artificial test setup, and ultimately I don't believe that it will yield any meaningful results for most of the readers here. 

 

I would much rather spend that time to figure out a way so you can have a listen to the REF 10 yourself in the environment you know and in the application it was intended to be used: enjoying digital music playback through a high-quality DAC and a good pair of speakers. Judging by the link you posted, I'm guessing you are in Germany or one of the German speaking neighboring countries, so let me know if you're genuinely interested in a demo. 

 

Best regards,

Julian

I am in Norway and it would be great if the Norwegian distributor had a demo Ref10 unit.

 

:-)

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  • 3 weeks later...

LENGTH OF WORD CLOCK CABLES

 

Antelope Audio says that the BNC cable connection stability begins to degrade after the 250th meter.

 

But maybe golden ears experience degradation after 30 centimeters? Does austinpop have any further evidence that 30 centimeters are a crucial limit for word clock cables?

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1 hour ago, austinpop said:

 

Nope.  I'm not making claims.

 

Just asking the question. Does master clock cable length matter? And referring to what SOtM have reported.

 

I'd rather just hear what Mutec - @julian.david et al. - have to say. 

 

No need for snideness.

 

 

 

I think extraordinary claims need extraordinary evidence. Your and SOTM's claim of 30 centimeters is as extraordinary as Antelope's 250 meters claim.

 

However, we know that Antelope is a big clock producer, delivering word clock gear to Hollywood productions and the like. Sotm is more of a boutique isn't it?

 

I too look forward to seeing what Mutec says. If they side with the Sotm claim or the Antelope policy of pretty long cable runs.

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5 hours ago, pam1975 said:

@austinpop did not *claim* anything. He's asking a question.

 

You on the other hand talk about Antilope's claim that connection stability degrades after 250m. 

He is talking about SQ as a function of cable length, not connection stability.

Pam, austinpop said, quote:

 

"The SQ dropped going from 0.3m to 1m".

 

Sounds like a claim to me. He used no qualifiers.

 

My intention was bringing some cold water into the discussion, separating audiophilia from audiophoolia, so to speak.

 

Don't you see there's a discrepancy between Antelope's suggestion of maximum 250 meters and austinpop's remark of 0.3 meters?

 

Antelope word clocks are used in Hollywood productions like the last Star Wars movie. Do you think Antelope will have their gear quality impaired due to cable length? Who has the most competence in said matter; the billion dollar movie industry or a Chinese hifi boutique?

 

However, I often find that there is no such thing as one universal truth. So a middle way is sometimes a good compromise. The compromise between Antelope's 250 meters and Sotm/austinpop's 0.3 meters is still about 100 meters.

 

Still, extreme clocks are delicate so maybe there is some truth to the claim that quality will be impaired somewhere between 0.3 meters and 250 meters. So I look forward to reading Mutec's take on this question.

 
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pam1975, there's an old (2010) discussion on clock cable length on Gearslutz:

 

https://www.gearslutz.com/board/music-computers/479654-clock-cable-length.html

 

The GS debate didn't conclude on a given, ideal length. However, nobody suggested that length should be below 1 meter.

 

Given the fact that word clocks have multiple outputs, imagine how the setup would look like if cable length were not to exceed 0.3 meters with, say 8, peripherals connected. Impossible to route 8 cables in that fashion, I think.

 

But I will await Mutec's answer because they're the ones who should know about signal strength etc. of their own clock.

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36 minutes ago, vortecjr said:

I appreciate your responses. I have one follow up question that I did not think to ask before. Is the USB input also subject to the re-clocking circuit that is influenced by the use of the REF 10?

In the same vein: Are alle the inputs of the MC-3+USB influenced, for example the AES-EBU input?

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41 minutes ago, julian.david said:

 

 

We are working on a compatibility list for DACs. There are definitely a few out there already such as the Esoteric D-1, D-02X and D-05X, TEAC NT-503, Antelope Zodiac, and we are expecting there to be more manufacturers jumping on the bandwagon in the future.

Would you add a list of compatible streamers (without DAC) as well?

 

:-)

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READING MATERIAL ON CLOCKS

 

I think many (including myself!) need reading up on clocks. So I thought I'd share this readworthy link, referenced by TapeOp:

 

http://pinknoisemag.com/pink-papers/pink-paper-002

 

Maybe Julian could tell us how the Ref10 compares with the other clocks mentioned in the article, i.e. both specifications wise and "philosophically" (i.e. the design idea behind the product).

 

It would also be nice if other readers would comment on the findings and impressions of the Pink Noise people in order to further our understanding of the Mutec Ref10.

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21 hours ago, modmix said:

From some tests since 2014 using various 10 MHz source, I too came to the conclusion that Jrms close to the carrier is one of the best figures to determine sonic quality of such a device used as reference to a MC-3+.

 

From Cybershaft rubidium clock...low priced option?:

 

REF 10 gives just 7 fs (10-100Hz) - using phase noise figures given above in this thread and http://www.abracon.com/phaseNoiseCalculator.php.

 

One has also take into account the signal form (eg. sinusoidal, squared) for one simple reason: the receiver has to detect at which point in time the signal did pass the threshold region. A faster transition gives less jitter added by the input stage. From my experience, a factor of 3 is a good number to compare these types of signals.

 

The devices listed above give sinusoidal signals, too my best knowledge.

REF 10 has a square wave output signal, => < 2 fs (10-100Hz), if my experience applies here, too.

 

hth

Ulli

 

 

Seems like the MSB 33 Femto (i.e. 33 femtoseconds for the entire frequency range) is a bit ahead of the Ref10, does it?

 

http://www.audio-focus.com/MSB/msb_femto_33_clock.html

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25 minutes ago, modmix said:

Reminds me of playing Autoquartett when I was a child - more speed, more power and the hack.

But - let's play it ,-)

And, I guess, we do talk about electrical properties and leave money out of the game...


Luckily we can simply compare what the respective manufacture gives on their respective page:

  REF 10    femto 33       freq.range
  28.8fs           31.8fs             1-100
    7.3fs            7.8fs            10-100 

  51.4fs          42.3fs       1-100,000
  43.2fs          28.9fs     10-100,000
unknown         1ps      0.1-100,000

 

Looks like we do have two winners - depending on the frequency range B|

From some years of soundwise comparing OCXOs I do have an idea which frequency range is of more importance when it comes to sq.


BTW: is there a stand alone Femto 33 (including case, psu, clock distribution and the like)?
If so, what kind of output signal does it deliver?

To my knowledge this femto 33 unit is to be embedded onto the MSB Dac-circuitry.

 

It's on another level, however, price wise compared to Ref10. As is all MSB gear (some of the most expensive you can get).

 

It would be nice to hear from Julian, given the phrase "industry leading" in the marketing material for the Ref10.

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Thanks for replying, Julian.

 

I think good designers should just take the bull by the horn and explain their design choices. Transparency is a big plus for competent designers.

 

One ssue remains, however: What happens to the OCXO performance when it's transferred from output via cable? What is the integrity of the signal when you introduce a cable (length, quality of cable) into the equation?

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  • 2 weeks later...

Julian, there have been some testers who report better sound after stacking MC-3+USB units.

 

How will the Ref10 fit into such a stacking project? Where should the Ref10 be connected to should a stack a MC-3+USB units? Should the Ref10 be connected to each MC-3+USB, the first unit or the last unit?

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