Directional Digital Cable

[tamarasue]

Hoping someone can assist me.   I recently purchased a 75ohm (RCA) Digital Cable.   One end has a red ring, the other white.    I assume this is to indicate direction as the shielding if often grounded at one end.    Can anyone advise which end is the source end? 

Thanks in advance.

[sandyk]

 

Quote

Hoping someone can assist me.   I recently purchased a 75ohm (RCA) Digital Cable.   One end has a red ring, the other white.    I assume this is to indicate direction as the shielding if often grounded at one end.    Can anyone advise which end is the source end? 

Thanks in advance

A 75 ohm (RCA) Digital Coaxial cable has to have the " earth" side at both ends connected to work correctly.

 Do you have a link to the cable that you purchased? 

[tamarasue]

Its a Transparent Cable - High Performance

 

no info on there site though

High Performance 75-Ohm Digital Link

 

 

[AussieMick]

If you look really carefully through the mesh sheath, you can read some printing underneath on the cable. It tells you direction.

[Ittaku]

Try it in both directions blinded and be surprised!

[tamarasue]

Thanks AussieMick   -  White writing on a silver sheath, barely visible, but I found it! 

And Ittaku  -  I've plugged it in both ways and despite my super sensitive ears - buggered if I could tell a difference!    I believe direction is so its earths to the destination end so just wanted to get it right so there are no hum etc issues at a later date. 

[Ittaku]

9 minutes ago, tamarasue said:

And Ittaku  -  I've plugged it in both ways and despite my super sensitive ears - buggered if I could tell a difference!    I believe direction is so its earths to the destination end so just wanted to get it right so there are no hum etc issues at a later date. 

Very good. This means you are not prone to the power of suggestion for there is no mechanism for a digital cable of that sort to actually be directional. Earth can't be directional in a cable like that so there's nothing to be concerned about.

Edited July 4, 2019 by Ittaku

[andyr]

1 hour ago, tamarasue said:

I believe direction is so its earths to the destination end

 

Nono - as 'sandyk' posted, in a coax cable the shield provides signal earth (whilst the centre pin carries the signal).  So the shield will be connected to the RCA plugs at both ends.

 

So it would be interesting to know why they wrote a direction on the silver sheath?  Can you tell us what the writing says?

 

Thanks

Andy

 

[tamarasue]

12 minutes ago, andyr said:

 

Nono - as 'sandyk' posted, in a coax cable the shield provides signal earth (whilst the centre pin carries the signal).  So the shield will be connected to the RCA plugs at both ends.

 

So it would be interesting to know why they wrote a direction on the silver sheath?  Can you tell us what the writing says?

 

Thanks

Andy

 

Spoke to the supplier and they said to install the cable in the direction of the writing.    Like I said - I couldn't hear any difference so it may be hog wash - but Transparent Audio are a decent cable company! 

[Ittaku]

7 minutes ago, tamarasue said:

Spoke to the supplier and they said to install the cable in the direction of the writing.    Like I said - I couldn't hear any difference so it may be hog wash - but Transparent Audio are a decent cable company! 

It's all Marketing drivel I'm afraid. Many years ago someone subjectively felt  that a cable sounded better in one direction than the other and ever since then most audio cable manufacturers have been claiming directionality on all the cables they make when in fact close to zero could possibly have any directional effect. You'll have to reconsider what the words "decent cable company" mean in light of that.

[Guest scumbag]

On 04/07/2019 at 12:26 PM, Ittaku said:

It's all Marketing drivel I'm afraid. Many years ago someone subjectively felt  that a cable sounded better in one direction than the other and ever since then most audio cable manufacturers have been claiming directionality on all the cables they make when in fact close to zero could possibly have any directional effect. You'll have to reconsider what the words "decent cable company" mean in light of that.

Another confirmation of why I have starting avoiding any "discussions" on this site.

[sir sanders zingmore]

6 minutes ago, scumbag said:

It's only a matter of time until Ittaku lobs in to tell us all "how it really is".

 

1 minute ago, scumbag said:

Another confirmation of why I have starting avoiding any "discussions" on this site.

and yet ….there you are 

[Nigel]

I am glad Ittaku saved the rest of us from posting "It's bullslip!". 

Not sure why you would want to stop such precautionary advice being given, Scumbag. 

Myabe you have history with Ittaku...

[AussieMick]

 https://youtu.be/sX4Cr8sfFkg

 

Thoughts?

 

[MLXXX]

On 04/07/2019 at 10:34 AM, tamarasue said:

And Ittaku  -  I've plugged it in both ways and despite my super sensitive ears - buggered if I could tell a difference! 

[tongue in cheek]Ah, but you haven't waited for the cable to burn in. Nor have you considered long-term listening fatigue. In any case, is your system resolving enough?[/tongue in cheek]

 

It turns out that, in practice, even ordinary 75 ohm SPDIF coaxial cable can be found to do the job. Please see my post immediately below, in response to a general query about cable directionality.

Edited July 11, 2019 by MLXXX

[MLXXX]

 

2 hours ago, AussieMick said:

https://youtu.be/sX4Cr8sfFkg

 

Thoughts?

 

I see that that link which may be easier to find at https://www.youtube.com/watch?v=sX4Cr8sfFkg&feature=youtu.be is Paul McGowan, highly experienced and persuasive presenter on audiophile matters, discussing cable direction.  He is rather non-commital on the topic in that video, though doesn't rule out the possibility altogether.

 

@AussieMick, for coaxial cable simply used for SPDIF signals, there's usually even less reason to worry about supposed subtle differences related to "cable direction". The device receiving the digital stream very possibly tidies it up and buffers it. If it is a good quality DAC, it will do that to the digital stream and reclock it. And even an amplifier with a built-in SPDIF coaxial input ought to be able to tidy up the signal.

 

So for the peace of mind of an audiophile who has acquired a relatively expensive length of coaxial cable just to carry a SPDIF signal, it would probably be best for them to avoid a listening test comparing their "high performance" 75 ohm coaxial cable with a similar length of ordinary audio grade 75 ohm coaxial cable with RCA connectors. (People have been known to report hearing no differences, disturbingly often. )

 

And if it's a short run of cable that's involved, the audiophile possessing an expensive 75 ohm coaxial cable should probably avoid substituting ordinary shielded audio cable for 75 ohm coaxial cable, as there is a strong chance that the ordinary shielded cable would work perfectly well; leaving all bits readable, ready to be buffered and reclocked by the device receiving the SPDIF stream. Such a result could be confronting and disappointing.

[Nigel]

1 hour ago, MLXXX said:

He is rather non-commital on the topic in that video, though doesn't rule out the possibility altogether.

I think that means he has a commercial interest in not discouraging potential (aka "gullible") customers. 

Despite this forum being quite technical and informative on how everything works, we have sponsors and other 'hidden' businessmen trying to stimulate the snake-oil market... such as power cables 

[Guest scumbag]

10 hours ago, Sir Sanders Zingmore said:

 

and yet ….there you are 

And yet so are you. You are part of the objectivist mob so I suppose you have to poke your nose in at some point. You guys are ruining stereonet one thread at a time. 

[sir sanders zingmore]

9 minutes ago, scumbag said:

And yet so are you. You are part of the objectivist mob so I suppose you have to poke your nose in at some point. You guys are ruining stereonet one thread at a time. 

Maybe I’m just being an objectivist, but I don’t see any evidence that SNA is  being ruined. 

 

There’s healthy debate which for the most part, is respectful (you should look at some other forums to get an idea of how good it is here).

 

Of course people sometimes disagree but that’s a good thing in my opinion. I’ve learnt far more from people who’ve challenged my ideas and beliefs than from those who simply agree. 

 

We need more GTGs and beer

[Assisi]

1 hour ago, Sir Sanders Zingmore said:

 

 

We need more GTGs and beer 

@Sir Sanders Zingmore

I agree with the GTG.  Maybe some red wine also.  Subjectivist me looks forward to seeing you somewhere soon.

John

[Guest scumbag]

2 hours ago, Sir Sanders Zingmore said:

Maybe I’m just being an objectivist, but I don’t see any evidence that SNA is  being ruined. 

 

There’s healthy debate which for the most part, is respectful (you should look at some other forums to get an idea of how good it is here).

 

Of course people sometimes disagree but that’s a good thing in my opinion. I’ve learnt far more from people who’ve challenged my ideas and beliefs than from those who simply agree. 

 

We need more GTGs and beer

It seems that you and others on this forum have either forgotten or never really grasped the concept of "discussion" or "debate" and as such these threads always descend into the same name calling and brow beating. Ironically you called me out about participating in this debate in my first post when I was not responding to the OP's question so by definition I was not involved in any debate or discussion about cable directivity.

Note the lack of people posting any alternate viewpoints on this thread. But then again, I guess that's how you guys like it.

[stereo coffee]

7 hours ago, MLXXX said:

 

 

I see that that link which may be easier to find at https://www.youtube.com/watch?v=sX4Cr8sfFkg&feature=youtu.be is Paul McGowan, highly experienced and persuasive presenter on audiophile matters, discussing cable direction.  He is rather non-commital on the topic in that video, though doesn't rule out the possibility altogether.

 

@AussieMick, for coaxial cable simply used for SPDIF signals, there's usually even less reason to worry about supposed subtle differences related to "cable direction". The device receiving the digital stream very possibly tidies it up and buffers it. If it is a good quality DAC, it will do that to the digital stream and reclock it. And even an amplifier with a built-in SPDIF coaxial input ought to be able to tidy up the signal.

 

So for the peace of mind of an audiophile who has acquired a relatively expensive length of coaxial cable just to carry a SPDIF signal, it would probably be best for them to avoid a listening test comparing their "high performance" 75 ohm coaxial cable with a similar length of ordinary audio grade 75 ohm coaxial cable with RCA connectors. (People have been known to report hearing no differences, disturbingly often. )

 

And if it's a short run of cable that's involved, the audiophile possessing an expensive 75 ohm coaxial cable should probably avoid substituting ordinary shielded audio cable for 75 ohm coaxial cable, as there is a strong chance that the ordinary shielded cable would work perfectly well; leaving all bits readable, ready to be buffered and reclocked by the device receiving the SPDIF stream. Such a result could be confronting and disappointing.

A cable stated as being 75 ohms, IMO stands a much greater chance of being 75 ohms from a recognised 

manufacturer of cable, such as Belden. To then place RCA's which are NOT 75 ohms either end, is telling you the cable is a fashion item, and not designed for proper operation. Physics dictates a true 75 ohm link will be provided with 75 ohm BNC connectors, requiring you to sometimes awkwardly also change to BNC where the cable connects.  

 

 

[MLXXX]

20 minutes ago, stereo coffee said:

To then place RCA's which are NOT 75 ohms either end, is telling you the cable is a fashion item, and not designed for proper operation. Physics dictates a true 75 ohm link will be provided with 75 ohm BNC connectors, requiring you to sometimes awkwardly also change to BNC where the cable connects.  

The official SPDIF requirements are for a 75 ohm impedance.  Traditionally, RCA connectors have been used in conjunction with coaxial cable intended for a SPDIF connection. The baud rate for audio signals sent via SPDIF is relatively low and the discontinuity in impedance at the RCA connector would be considered to have a negligible impact for this low baud rate application, from an engineering viewpoint.

 

But yes, use of  75 ohm cable is perhaps overkill. I certainly remember times when I've used a short length of ordinary shielded audio cable for a coaxial SPDIF connection without any apparent ill effects, if there was no coaxial cable on hand.

[stereo coffee]

1 hour ago, MLXXX said:

The official SPDIF requirements are for a 75 ohm impedance.  Traditionally, RCA connectors have been used in conjunction with coaxial cable intended for a SPDIF connection. The baud rate for audio signals sent via SPDIF is relatively low and the discontinuity in impedance at the RCA connector would be considered to have a negligible impact for this low baud rate application, from an engineering viewpoint.

 

But yes, use of  75 ohm cable is perhaps overkill. I certainly remember times when I've used a short length of ordinary shielded audio cable for a coaxial SPDIF connection without any apparent ill effects, if there was no coaxial cable on hand.

Each of these giving in's to marketing machinery, ie using RCA's and your suggestion of  "using a short length or ordinary shielded audio cable for a coaxial SPDIF connection without ill effects "is explained in Malcolm Hawksfords You Tube lecture. Malcolm explains many of the short cuts manufacturers take, and looks and asserts the science and steps very much needed,  with doing digital properly.    

 

 

Edited July 12, 2019 by stereo coffee

[AussieMick]

1996 is a long time ago. I know physics hasn’t changed, but hasn’t measurement? Both tools and the idea of what’s important to measure?

 

As for directionality, I know one manufacturer simply marks the direction in which the cable was drawn, and suggests people can make up their own minds as to which way might sound better, if at all. Pragmatic.

 

I hear differences in cables. I think most do. Attaching better/worse labels is probably personal and system dependent.

 

I have heard dramatic difference in cable direction, but I haven’t experimented with digital cable. Perhaps I should. If I can hear a repeatable change, but can’t find a suitable scientific/engineering reason, than that causes me to think we’ve not discovered what to measure in order to explain it. After all, that’s just scientific curiosity. Quite important in the history of the human race, wouldn’t you say?