G-01 & 10MHz Output Cable Impedance

[CGabriel]

I guess we didn’t get on the email list.

What you are saying is quite true. There are precious few, actual, clock cables available.

Esoteric Mexcel cable is one.

Shunyata Venom Clock-75 (Coaxial, 75 ohm characteristic impedance)
Shunyata Alpha Clock-75 (Coaxial, 75 ohm characteristic impedance)
Shunyata Alpha Clock-50 (Coaxial, 50 ohm characteristic impedance)
Shunyata Sigma Clock-50 (Coaxial, 50 ohm characteristic impedance)
Shunyata Sigma Clock-75 (Coaxial, 75 ohm characteristic impedance)

And yes, the connectors are also the correct impedance for each cable.

[justubes]

And of course, not forgetting Chris Sommovigo's, grand daddy of digital audiophile cables

I have been using the a Acrolinks 5100 BNC and 6100 RCA since but cannot get hold of further ready stocks of 75ohm for testing with my Esoteric clock, Cybershaft op16 and Mutech MC3.1+ and Quartlock rubidium gear. Unfortunately no Clock50 or Clock75 cables are even stocked by the local dealers.

It would be of great interest if the reviewers of the Clock 50 and 75 could elaborate on the differences and further insights on the sonic characteristics and benefits between these used in both the correct and incorrect application so more users can make a decision on which cables to buy.

10M sine waves would obviously benefit form using the 50 ohm variant and 75 ohm for PLL signals now that there are many new clocks being marketed.

Apart from gear accepting 10M reference clocking, it is of great interest why gear like DCS choice on using a lower PLL based master clocking and was the choice based on lower jiteer/phase noise at these frequencies.

Some nagging question for me are that if equipment both accepts a clocking at 10M sine and other various Master clock frequencies as in the Esoteric K-01x from the Esoteric which i use along with many forumers here.

The problem is that there is only 1 clock input BNC, which is 75ohm.

So sending a 10M sinewave to the player, would the choice of a Clock 50 or a Clock 75 be correct? Impendence mismatch either way?

It has been a while back were i had correspondences with Clock manufacturers where if i recall, the clock distribution circuit of their 50 ohm sinewave output could be factory requested to be set at the output for 75 ohm if requested. All via resistor network, if i am not wrong.

Many questions, but haven't found the answers! Hope more light can be shed via this thread.

[CGabriel]

Originally Posted by justubes

And of course, not forgetting Chris Sommovigo's, grand daddy of digital audiophile cables

I have been using the a Acrolinks 5100 BNC and 6100 RCA since but cannot get hold of further ready stocks of 75ohm for testing with my Esoteric clock, Cybershaft op16 and Mutech MC3.1+ and Quartlock rubidium gear. Unfortunately no Clock50 or Clock75 cables are even stocked by the local dealers.

It would be of great interest if the reviewers of the Clock 50 and 75 could elaborate on the differences and further insights on the sonic characteristics and benefits between these used in both the correct and incorrect application so more users can make a decision on which cables to buy.

10M sine waves would obviously benefit form using the 50 ohm variant and 75 ohm for PLL signals now that there are many new clocks being marketed.

Apart from gear accepting 10M reference clocking, it is of great interest why gear like DCS choice on using a lower PLL based master clocking and was the choice based on lower jiteer/phase noise at these frequencies.

Some nagging question for me are that if equipment both accepts a clocking at 10M sine and other various Master clock frequencies as in the Esoteric K-01x from the Esoteric which i use along with many forumers here.

The problem is that there is only 1 clock input BNC, which is 75ohm.

So sending a 10M sinewave to the player, would the choice of a Clock 50 or a Clock 75 be correct? Impendence mismatch either way?

It has been a while back were i had correspondences with Clock manufacturers where if i recall, the clock distribution circuit of their 50 ohm sinewave output could be factory requested to be set at the output for 75 ohm if requested. All via resistor network, if i am not wrong.

Many questions, but haven't found the answers! Hope more light can be shed via this thread.

We did all of this research and exhaustive tests, over a period of two years, to determine exactly which cable parameters have an audible effect when used in a digital audio system. In the latter stage of this research we enlisted volunteer beta testers. These people were chosen based upon their access to multi-component digital systems - usually Esoteric or dCS systems. And that they had extensive experience using several different brands of digital cables along with the use of reference master clocks. The primary purpose of the beta tests was to determine several things related to cable characteristic imdedance. First, you need to know that digital cables carrying frequencies that are relatively modest (10Mhz & 22 Mhz) do not ‘technically operate as a transmission line if the length is shorter than about 4 meters. Which has lead many people to claim that you don’t actually need a cable that has a specific characteristic impedance. Many audiophiles with complex digital systems, running master clocks, have anecdotal evidence that the characteristic impedance was important. So, the purpose of the tests was to first determine: a) does the characteristic impedance have any audible effect and b) does using matched impedance cables have a positive effect or just different and c) if the input and output interfaces have different impedances (50 & 75), what impedance should the cable and connectors be for best performance.

Some of the beta testers hang out here at AA including SCAudiophile and Ariess. Perhaps one or both will chime in with their experience during the tests.

The knowledge we gained has lead us to the conclusion that characteristic impedance is, indeed, critical to extracting the best performance from digital audio equipment. Which is why we offer a comprehensive line of ‘precision matached impedance’ digital cables. Including 50-ohm cables that are required for the Esoteric rigs.

[justubes]

CGabriel, thanks for your comprehensive reply!

It does indeed like like the direction of Esoteric is to focus just on the universal 50 ohm sine wave distribution for their new line of clocks.

Of interest, would the the Alpha50, presuming it is the correct and better impedance match sound and perform better than a Sigma75?

Hope to gain more insights in this thread... Choices... Choices...

[CGabriel]

Originally Posted by justubes

CGabriel, thanks for your comprehensive reply!

It does indeed like like the direction of Esoteric is to focus just on the universal 50 ohm sine wave distribution for their new line of clocks.

Of interest, would the the Alpha50, presuming it is the correct and better impedance match sound and perform better than a Sigma75?

Hope to gain more insights in this thread... Choices... Choices...

What the beta tests made clear was that a digital interface performs best when the rated ‘characteristic imoedance’ is followed.

It is not the ‘only’ cable specification that contributes to the audible performance, but when all other parameters are equivalent, the impedance is paramount to extracting the best performance from your rig.

[SCAudiophile]

Apologies for the late reply,...running hard these days and on the way to the airport again in about an hour !!! Here is something I wrote up for a someone else asking this question via email recently....this will be a quick copy-paste and I apologize in advance for any errors on my part,....

TESTING STORY (50 versus 75-ohm, proper cables,"does it matter...?");

I was lucky enough to participate in 4+ month dedicated test with several audiophiles around the world, all with different equipment stacks (DCS, Esoteric, Aurender, and several other vendors' products) and different clocks (DCS, SRS, BVA, Esoteric, Cybershaft) during which time we had no idea of each others' identity, location or equipment and clock equipment lists. We were all sent the same, uniform-looking cables with only colored tags on them to tell them apart. All cables were 1.5 meters in length. The only thing that was different on some of the cables were the use of 50-ohm versus 75-ohm BNC connectors which are easily discernible as to which is which due to a key visual difference regarding the dielectric around the center tap. As it turned out though, the vendor lead for the testing had mixed different cable specs (50 and 75) with different connectors so at the end of the test among other things we found that there were pure 50-ohm cables, pure 75-ohm cables, 50-ohm cables with 75-ohm connectors and 75-ohm cables with 50-ohm connectors. Clocking also spanned 'word clocks' as well as 'master clocks' and clocks that had taps for both word clock outputs as well as master clock output frequencies...
We were instructed to test against our local ‘reference’ cables; in my case it was against WW Platinum Starlight 75-ohm BNC, a Kubala-Sosna EMOTION 75-ohm and a custom-built EMOTION 50-ohm which has its own interesting history and contents that I will not go into here, and an Esoteric 8N-A2000 with
The 8N-A2000 arguably the acknowledged heavyweight champ for years in the world of true 50-ohm clock cables. Not all digital cables are meant to be or suited for clocking purposes as has been noted before.
As an aside, all testers came from some of the same but also different forums. We were given strict instructions not to mention we were testing anything related to cables for 50 or 75-ohm clocking or any other aspect of the test. To remove any potential bias from the equation, the cables tested were NOT production cables or prototypes contrary to what we thought. They literally were telecommunications high-speed quality cables from a major OEM rated for 50-ohm or 75-ohm with BNCs applied as mentioned about also from high-bandwidth telecom cables/parts suppliers. All test cables were enclosed in simple black tech-flex with no markings at all beyond the color tags.

In each and every case, all testers would summarize their multi-week testing with each cable (long enough to ensure day 1 through day n and "n+" impressions (i.e. from initial connection through full 2-week burn-in and beyond privately to the test lead and what material was used to test (RBCD, SACD, streaming, etc...) and the cable color-tagged under test.
We were all asked to test across different source types (and all did...). The surprising thing when all was said and done 5 months later was that the notes of each tester were copy-pasted verbatim into a single doc and sent with only first names mentioned. Some started the test of the opinion that 50 versus 75 should matter and be adhered to (why else would high-end vendors like Esoteric go to such lengths to cover this in their markings, manuals, etc... after all?!?) and some started predisposed to the common forum/vendor-speak of the last year or so,...("as long as you are not using long cables it does not matter,...they won't operate like a transmission line at short lengths,...").

Summary: The way I read the testers’ output and my own is that without exception all testers' experience was more or less of the form that 50-ohm cables on 50-ohm circuits result in the best overall sound quality, precision of the overall musical experience and note-by-note precision, duration, size, color, musicality, etc.....AND using 75-ohm on a 50-ohm circuit resulted in degraded sound quality, less precise and accurate imaging, bass articulation in particular, etc...Furthermore, using a proper 50-ohm cable on a 75-ohm circuit actually sounded better in several ways that a proper 75-ohm cable BUT not the reverse config.
There were interesting results with 50-ohm cables with 75-ohm BNCs on a 75-ohm circuit BUT the reverse (75-ohm cable with 50-ohm connectors on a 50-ohm circuit) was to be avoided due to detrimental effects on the sound, imaging, etc....In short, through this exhaustive test seemed to prove that despite what even Esoteric is saying today, 2 years after the discontinuation of an Esoteric 8N-A2000 pure 50-ohm cable which is still one of the finest in the world (during whose manufacturing & sales years Esoteric was singing a VERY different tune and advised clients that it DOES matter), it seems that using the properly rated cable on a given circuit DOES make a difference regardless of length due to the frequency at which these signals occur.

Footnote: After the testing as well as before had me using various high-end 50 and 75-ohm cables from 3 different manufacturers including 2 coveted and rare Esoteric-Mexcel 8N-A2000s but also a couple of high-end custom builds and 2 stock builds from 2 different/other manufacturers. In all cases before and also after the above 5 months of testing I admit that I always heard a difference and preferred the 'match the specs and RTFM approach with cables and gear but in the last 5 months I've had the good fortune of being able to move to the best 50-ohm cable I've used ever, the Shunyata SIGMA “CLOCK 50” and have concluded once and for all that 50-ohm very much matters where it's called for.

I will also say that my last day in testing labs or other 'very specific places' where I had any hands on or desire for that level of details for engineer-level tests, specs, etc....was in the early 1980s. For audio, and the testing above, the results I'm talking about come from the ear/hearing level of focusing only the music. For my money, I'll stick with what I heard, i.e. that where 50-ohm is called for and the same for 75-ohm in clocking or other applications, the best thing to do for the best and most musical and accurate result is to match cables to connection types and make sure you have components from manufacturers that also properly implement the spec in each case as this is all for naught if they don't stick to a tight implementation of 75-ohm versus 50-ohm for each application where it's called for.

All FWIW and IMO..

[brodricj]

Originally Posted by CGabriel

..It is not the ‘only’ cable specification that contributes to the audible performance, but when all other parameters are equivalent, the impedance is paramount to extracting the best performance from your rig.

During your internal engineering stages of the process, particularly with the stock OEM cables used in the beta, was there ever any attempt to quantify electrical characteristics of inputs and outputs (i.e. what was going in compared to what was coming out) for the various combinations of cables and connectors, and account for any differences across the interface?

[brodricj]

Originally Posted by justubes

...It does indeed like like the direction of Esoteric is to focus just on the universal 50 ohm sine wave distribution for their new line of clocks..

Really? G01X and G02X are both new model clocks and they both have 50 ohm and 75 ohm outputs. K1 is different. It's also a new model but they have dropped support for 75 ohm.

You would think that, given Esoteric only build 75 ohm Mexcel clock cable now, that they would drop support for 50 ohm output of their clocks. So it doesn't make sense that they build K1 without 75 ohm.

[CGabriel]

Originally Posted by brodricj

During your internal engineering stages of the process, particularly with the stock OEM cables used in the beta, was there ever any attempt to quantify electrical characteristics of inputs and outputs (i.e. what was going in compared to what was coming out) for the various combinations of cables and connectors, and account for any differences across the interface?

Yes, we did all the engineering tests prior to the beta subjective listening tests including impedance analysis using a Hioki impedance analyzer and jitter measurements using an Audio Precision Analyzer. These technical parameters and tests are well known. What was not well known and debatable was the correlation between various digital cable technical specifications and digital audio subjective performance. The impedance tests were only one set of tests performed. We also tested the correlation between other cable specifications to determine which of them have a strong correlation to subjective audio performance. Some of these are: transmission velocity, frequency bandwidth, dielectric absorption, shielding materials and methods, simple resistance and interval impedance variance. Which these are and aren’t important to the design of audio digital cables we have chosen to keep proprietary. Obviously, we decided to release the information about “characteristic impedance” and its importance even when a cable is not technically functioning as a transmission line due to the length of the cable.

[justubes]

Thanks Mark, it is much clarified now.

Besides, was the Alpha, Sigmas unmarked also included in you test or just various industry 50/ 75 ohm cables variants lesd to using them after the test as your choice of cabling?