S/PDIF Cable

[manisandher]

Hey Peter, have you ever discussed carbon cables with a particular neighbour of yours?

Mani.

[PeterSt]

No, but if he steps inside (Van den Hul) he will probably start crying, and next will think I can't be serious about such a subject.

[manisandher]

Thinking about it, I probably liked his 'The Second' cables because I was using a pair of B&W N802 speakers at the time, which are just way too bright ordinarily. I sold these to my sister, and still have to cover my ears whenever I'm at her place, because they sound so grating... even with the 'darkness' that the VdH The Seconds bring to the party.

Nice article BTW; http://www.empiricalaudio.com/computer-audio/audio-faqs/short-versus-long-cables. Cables really are a bottomless pit though. Like I said earlier, there are much bigger nuts to crack in audio... IMHO.

Mani.

[AUDIODIDAKT]

Thnx Mani for stepping in, (and Peter)

And for providing some decent links
I have a disc somewhere with all my links from the past on making good cables.
But can't find a damm thing anymore. (long time ago)
And things are changing at such a fast rate.

Boleary's wish in length is too short, also my advise 0.80m-1.50m certainly not shorter.

About those connectors indeed they should be 75ohm, but I can not believe the M-audio or MSB or Hiface has perfect 75ohm Receptacles, (yea, BNC on HiFace, OK)
or even a precision 75ohm resistor on their part.
It doesn't stop with just the cable, when you take a look inside your equip. you start to wonder why invest in a expensive cable at all, without doing the inside too.
And with equipment I also mean: the expensive sh|t too.

There are 75ohm RCA connectors indeed.
http://www.canare.com/ProductItemDisplay.aspx?productItemID=40
But you have to look what connector fits the Belden 1694A cable for eg.

Personally I have good experiences using Eichmann on WBT Next-gen Receptacles (analog and digital)
But then again for digital BNC is better and cheaper, but not always do-able, and if you make just 1 cable,
you have to buy a BNC krimp-tool too.(??$)

Btw. I always peal off the outside PVC cover from the cable and use teflon plumbers tape instead.
And I always make a seperate ground connection instead of using the outside shielding mesh of the cable)
Leave the mesh and foil in place, but don't connect it to ground, use seperate wire for that.

But your options are still open Boleary............
Don't make your decision that fast, do some reading about the subject. (you don't have the hiface yet, anyway)

You could also try to get some canare 75ohm RCA connectors, (US only, I believe) they are much cheaper then eichmann (maybe 15$ per 2)

And for last, its always hard to judge, when not listened to what you actually buying.
But you have no choice with DIY.
And dealers that provide a decent means of trying them out, mostly provide you with far too expensive cables.
But don't forget you always have the right to return after several days. (even if you buy on the internet)

getting crazy already...hehe

Grtz

Roy
 

[AUDIODIDAKT]

From the thread, apparently the old Belkin Synapse Platinum Digital cables (the blue ones from the 1990s) are the 'dog's bollocks', as we say here in the UK. You may notice that there is a poster called 'miab' who is offering these cables for $65 each plus shipping. I've just ordered a couple of these from him, and they should be in the post to me right now. I'm hoping to be able to convert one to BNC and use it for my wordclock. Assuming I don't screw it up and need the other one, I may have one spare. I'd be happy to sell it for the price I paid for it (even if I'm hit with customs duty, the price shouldn't be more than £60 plus shipping). Alternatively, you might want to contact miab directly to ask if he has more...

Hey Mani,

A good SPdif cable is important because data and clock are combined in one signal.
So if data and clock are split up, cable becomes a bit "less" important

Do you have experiences in using different cables on just the wordclock ??

I thought this should only be a decent shielded 75ohm cable with BNC connectors.
Nothing more nothing less.
Or maybe this is actually what you are doing.

Roy

[AUDIODIDAKT]

Also a good site for DIY and cables:

http://www.vhaudio.com/

[PeterSt]

So if data and clock are split up, cable becomes a bit "less" important

Maybe not Roy. Because then both have a relation in separate cables.

[Ava12]

I'm currently 'designing' the digital inputs of my new dac and the outputs of my sources (mainly the M-Audio FW interface of course^^) and it struct me, why not use lab-like cables for the SPDIF signal like Aircell 5 or RG58/RG214. Well I'll try this.
My question is, are there different BNC plugs for 50Ohm and 75Ohm? Or is it one and the same?
Greetz Ava

[PeterSt]

The BNC plugs are different too. But why use a 50 Ohm cable where 75 is "needed" ?

[Ava12]

You're right why hastle, I thought there're higher quality cables in 50Ohm (RG214) but ok, then these are only better at higher frequencies than the 2.8MHz, we're using.
It wouldn't have made a difference to just use 50Ohm resistors instead of the 75Ohm ones, that's why I thought "just try"^^.
I'll try some RG59 then, with 0.1% 75Ohm resistors
Greetz

[AUDIODIDAKT]

The value for the impedance depends on the input resistor.
Kinda impedance correction, if resistor and chip-to-chip connection is 75ohm.
This rules out the total capacitance of cable.
Correct me if I'am wrong here.

also:
75 ohms: The characteristic impedance 75 ohms is an international standard, based on optimizing the design of long distance coaxial cables. 75 ohms video cable is the coaxial cable type widely used in video, audio and telecommunications applications. Generally all baseband video applications that use coaxial cable (both analogue and digital) are matched for 75 ohm impedance cable. Also RF video signal systems like antenna signal distribution networks in houses and cable TV systems are built from 75 ohms coaxial cable (those applications use very low loss cable types). In audio world digital audio (S/PDIF and coaxial AES/EBU) uses 75 ohms coaxial cable, as well as radio receiver connections at home and in car. In addition to this some telecom applications (for example some E1 links) use 75 ohms coaxial cable. 75 Ohms is the telecommunications standard, because in a dielectric filled line, somewhere around 77 Ohms gives the lowest loss. For 75 Ohm use common cables are RG-6, RG-11 and RG-59.

[AUDIODIDAKT]

The reason why the cable must have a for eg. 75ohm load,
is because the impedance of a cable is changed with frequency.

If there is no 75ohm load, mismatch will happen at certain freq.

but there is also:

risetime, dispersion, skin effect etc etc
also the architecture of the cable, the distance between dataline and ground.

[manisandher]

Do you have experiences in using different cables on just the wordclock ??

I thought this should only be a decent shielded 75ohm cable with BNC connectors.
Nothing more nothing less.
Or maybe this is actually what you are doing.

Yes, this is exactly what I'm doing.

I haven't tried too many BNC wordclock cables. The one I use at the moment is a very reasonably priced one made by a UK company called Trichord (trichordresearch.com). As you said, it's a simple shielded 75ohm cable with BNC connectors - nothing more, nothing less.

Mani.