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Author Topic: CD Players transport differences?  (Read 10003 times)

Sahib

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Re: CD Players transport differences?
« Reply #15 on: September 12, 2006, 05:33:23 PM »


I actually picked up a Leader CD jitter meter from e-bay about six months ago. But never tried it. It looks pretty straight forward and this could be a good time to get to learn it. I'll tell the wife I have urgent work to do over the weekend and spend some time with it. Anybody has used one before?
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danlavry

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Re: CD Players transport differences?
« Reply #16 on: September 12, 2006, 08:21:53 PM »

Ronny wrote on Tue, 12 September 2006 20:52



Yes, but is any converter actually totally 100% jitter free? Ala what we old timers used to call the holy DAC. Jitter immunized maybe, jitter free, I'm not so sure. If it's not audible but still measurable, that doesn't make it a 100% elimination of all jitter. For all practical audio purposes the reduction of jitter well below audible should be sufficient, should it not?


Yes, if you can get jitter to be low enough, but what is low enough? The problem is that the ear can hear very low jitter, and it is not all that easy to accommodate such low jitter levels.

BTW, when talking about jitter, it is too simplistic to think of one number. The ear sensitivity varies greatly when you change the frequency content of the jitter.

regards
Dan Lavry
http://www.lavryengineering.com
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Sin x/x

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Re: CD Players transport differences?
« Reply #17 on: September 13, 2006, 02:09:04 AM »

Jon Hodgson wrote on Tue, 12 September 2006 13:13

Sin x/x wrote on Tue, 12 September 2006 18:40

Jon Hodgson wrote on Tue, 12 September 2006 07:49

Sin x/x wrote on Tue, 12 September 2006 12:26


The quality of digital audio depends only on the quality of the converters.
If you hear sound difference between cd-transports, there's a design fault in the dac.


Dan has a good paper on jitter and phase locked loops on his website.



I can't find the paper on jitter and phase locked loops on Mr.Lavry's website.


Look on the support page, "White Papers"->"On Jitter"
Quote:

Jon Hodgson wrote on Tue, 12 September 2006 07:49


A perfect transport would have zero jitter on the output.

A perfect PLL would have 100% jitter rejection, a perfect PLL is not easy, which is why Lavry products have CrystalLock.

If you can hear a difference due to jitter on the output of the transport, then they are BOTH imperfect.



No, only the pll's in the converter needs to be good enough. Then all jitter is rejected.


And how does that contradict what I just said? For you to hear a difference caused by jitter requires that there be jitter in the first place, AND that your converter does not reject it completely.




We don't disagree.
But if you hear a difference between digital cables/transports, don't blame the cables/transports.

Thanks for showing me Mr. Lavry's paper on jitter.
As far as my knowledge goes it's truthfully.

It also agrees with my statement: If the dac is properly designed, all jitter is rejected.



So if a converter reacts to different cables, transports or needs an external jitter free master clock.
Throw it in the bin.





P.s. Put the "Proper word clock implementation" thread back where it belongs.


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