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Jitter and 75ohm cable length

I have read a number of papers on how cable length plays a role in Jitter between transport and DAC. After all of the dust settled I arrived at no sound conclusion, on paper, so I decided to use the ears of my 17 year old budding Audiophile to settle this by LISTENING! My transport is a Wadia 171i (WAV/LossLess files)and my DAC is a Cambridge AZURE 840C. I had three cables in my test, my 1M Kimber D-60 illuminations, a 3' HAVE/Canare and a 6' HAVE/Canare. All three cables sounded good, but in the end the victory landed on the 3' HAVE/Canare by a fair margin followed by the Kimber and last the 6'HAVE/Canare. In my readings I came across a number of articles saying you should use at least 1.5M of cable to reduce reflections in the cable so as to not harm the clock signal, yet an RF engineer said this was a bunch of "Bunk" and 1M would be better, in fact he said the shorter the better. So, forgive my verbosity, what are your thoughts and experience in this area? My 3' $25 HAVE/Canare beat up my $390 Kimber, I believe due to proper honest 75ohm terminations vs standard RCA connectors, and as far as length goes, at least in my system, 3' was by far the best. Thanks!
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almarg
9,670 posts
 
Hello Beolab,

I would proceed based on the comment by the dCS person, which pertains to your specific equipment, rather than on the more general guideline of 1.5 meters.  As I said in an earlier post in this thread:
Summarizing all that has been said, I would put it that a length of 1.5 meters ... stands a better chance of being ideal than any other length. But as have been cited there are many system dependencies and cable type dependencies which conceivably could result in other lengths being better in some cases.  
Also, it's worth noting that the impedances of BNC connectors are more accurate than the impedances of RCA connectors.  And I would suspect that the impedances of your dCS equipment that the cable would be connecting are more accurate than the impedances of a lot of other digital equipment.  Both of those factors will minimize the reflection effects which are a key factor in the rationale for 1.5 meters.

Regards,
-- Al
 
beolab
6 posts
 
Thanks for your advice! 

What is your oppinion on this interesting cable from Van Den Hul 
http://www.vandenhul.com/products/cables/audio-video/mc-silver-it-mk-ii-75-ohm-halogen-free

Have a great Sunday

/ Fredrik
beolab
6 posts
 
Or another alternativ could be to use a true 75 Ohm Canare BNC SDI 12 GHZ UHD video cable, or what is your thaughts about this? 

https://www.bhphotovideo.com/c/product/1338226-REG/canare_cal55cuhd003_12g_sdi_4k_uhd_single_channel...

Or would you choose a more specific word clock cable like Laird with Neutric BNC even if it got vorser specs on paper ? 

https://www.bhphotovideo.com/c/product/1021809-REG/laird_digital_cinema_sd_tcd1_01_sound_devices_bnc...

Or the old but proven Apogee Wide Eye 75 Ohm Canare Cable: 
https://www.amazon.com/Geistnotes-Apogee-Clock-Cable-WE-BB/dp/B01N3AL6WY?th=1&psc=1


Thanks for some guidence before ordering. 




@almarg 
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almarg
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@Beolab

Hello Fredrik,

As far as I can tell from the descriptions and specs all of those seem like reasonable choices. However the indication that the Van den Hul cable has a minimum safe bending radius of 70 mm strikes me as a bit worrisome. Also, I’m guessing that it costs a good deal more than the others, while not necessarily providing better performance in your application.

Perhaps a good way to proceed would be to order both of the cables that are sold by B&H, since they cost so little, and determining which one performs best in your system, if in fact there is any difference at all.

Good luck. Regards,
-- Al

beolab
6 posts
 
Thanks for your support and advice, i think the most superior cabel spec wise is the Canare 12 Ghz 4k cable, but the only thing that makes me hesitate is that the cable is optimized for 12 Ghz frequencies when it comes to  video signals.

Will probably buy them all three and see, but i need three of every cable. 
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