S/PDIF out OR Optical out

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TdougTMT

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Hey Guys! Im completely brand new to this forum, so bare with me!
Im looking to get the Digi 003 and the ART DPS II.
so my question is, Whats the best way to connect them?
S/PDIF Out from the ART to the 003's S/PDIF in?
or, Optical Out from the ART to the 003's Optical In.
or does it even make a difference?
Thanks.
 
S/PDIF (Sony-Philips Digital Interconnect Format) is a data format that can be fed either via co-axial cable or a TOSLINK fibre optic cable.

So...basically, it shouldn't make any difference. I tend to use the fibre but that's just because I tend to have a bunch of lightpipe cables around because I use ADAT for a lot of things.

Bob
 
Bobbsy is correct. Technicly, they're both S/PDIF. One is in the optical domain, the other coaxial.
 
I use the optical S/PDIF approach because:

1. Optical cables are cheaper than good coaxials

2. Optical connections are not subject to electromagnetic interference, so you can run them over power cables.

Richie
 
Richard Monroe said:
I use the optical S/PDIF approach because:

1. Optical cables are cheaper than good coaxials

2. Optical connections are not subject to electromagnetic interference, so you can run them over power cables.

Richie
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1. True, but optical cables are more easily damaged. Runs are limited to <20' and they don't like to be bent into tight turns.

2. Actually, they are vulnerable to EMF's. I think you meant to say they reject RFI.

Drone.
 
Drone_21042 said:
1. True, but optical cables are more easily damaged. Runs are limited to <20' and they don't like to be bent into tight turns.

2. Actually, they are vulnerable to EMF's. I think you meant to say they reject RFI.

Drone.
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EMF interference on a fibre optic? I don't think so. Just because light is part of the EM spectrum, doesn't mean they can pick up noise for mains cables.
 
Bobbsy said:
EMF interference on a fibre optic? I don't think so. Just because light is part of the EM spectrum, doesn't mean they can pick up noise for mains cables.
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I think so. Read a few white papers. Like this one.

Note how even fiber optic manufacturers (like AussieCom there in Australia- my father in law was once on the board) do not say "immune" to electromagnetic fields. They often, and correctly, say 'resistant'. And the main reason for it's resistance? The aramid/yarn structure built around it that acts as the primary EM shield.

Even if you have the highest caliber of glass (AT+T) and the design of the cable seeks to minimize EM nasties, you will have a significant reduction, but it is NOT 'immune'. It's a common misconception. Furthermore, that type of cable is very expensive and hard to find. Your average user does not have it, nor will they be able to easily find it.

Now, RFI? It is damned near immune to that....but again...not entirely. When you look at the cable (product) as a whole there are parts of it that could potentially pick up RFI and pass it along. Fiber optic is great but it was hyped up a lot. Most high end users I know still prefer coax.

With regard to 'noise', remember this is a digital cable. We're concerned about jitter and jitter is caused by electromagnetic field interference. When you compare a toslink cable to a coax you have to be concerned with precise ones/zeros delivery.
 
Thanks for the detailed explanation and the link. I stand corrected. All I can say, is that in the real world, power cables don't create the kind of EM interference with optical cables that they do with coaxial cables. And the ones I'm talking about are relatively cheap ones. Again, thanks for the clarification.-Richie
 
Richard Monroe said:
Thanks for the detailed explanation and the link. I stand corrected. All I can say, is that in the real world, power cables don't create the kind of EM interference with optical cables that they do with coaxial cables. And the ones I'm talking about are relatively cheap ones. Again, thanks for the clarification.-Richie
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Thank you, I appreciate that. It's hard to sound informative without sounding like an asshole...the whole web syntax thing. And I agree with you that cheap optical cables will far outperform a cheap coax...no doubt about it.
 
With respect, Drone, the White Paper you linked to actually states (on page two):

Security: Optical fiber is the most secure transmission medium, because it is immune to
EMI and Radio Frequency Interference (RFI). Since fiber transmits light rather than
electricity, it is not affected by the EMI from power, radio or microwave sources.
Furthermore, fiber is immune to crosstalk and is extremely difficult to tap – qualities that
cannot be claimed by copper. While information security has led to wide use of fiber by
financial institutions and the military, it is also extremely important to the average small
business and factory owner. Signal interference can pose a huge problem to factory
applications and other areas with a variety of electronics if copper is their only current
solution.
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Light cannot be affected by magnetic fields or radio waves. If a fibre optic link is in any way affected by EMI or RFI then, by definition, the interference must be in the electronics at either end, not the fibre itself after the data is converted to light..

As for "high end users", if they choose coax over fibre, it's because there are distance limits on the pro-sumer formats like TOSLINK and because, in situations where users have the ability to make their own cables, few can work with fibre optics.

Consider this: in many cases satellite feeds of data, video and audio from continent to continent have been replaced by undersea fibre optics. These undersea cables contain multiple fibres and also high voltage copper wires to power relay electronics at intervals along the route. If a fibre 4000 miles long doesn't pick up any EMI or RFI from the electric supply built into the same casing, is there going to be an issue with a 3 foot cable in a home studio?

But I repeat, light is not affected by electricity, magnetism or radio waves and the white paper you linked to confirms this.
 
Actually, the white paper ALSO says "resistant", and it is conflicting but consider this: My father-in-law has done well in the fiber optic business and it's something he would share information with me about. He sat on the board of one of the biggest fiber optic companies around and he told me a dirty secret was that the medium was not totally immune to EM fields. When you hold a fiber optic cable in your hands- is it made of pure light!? There's more to the product than the light transmission. Look at how they are manufactured and consider the materials they blend the glass with. The internet is overflowing with the phrase "fiber optics are immune to EMI/RFI", but they are only considering one element ala'carte. To make you see it my way would mean I would need to overturn the vast amount of misinformation out there and I lack that power and influence. You might think it's better to believe the marketing end of things than to believe me, and I'm OK with that. I'll know differently, and I'm OK with that to.
 
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That's one of the beautiful things about not being an engineer. I can only draw my conclusions based on empirical research (in other words, actually doing it). Yes, you can measure the amount that light is bent by the gravitation of the sun with a laser, but for all *practical* purposes, light is immune to gravity. OK, when you start to plot trajectories to Mars, that may become a *practical purpose*. I'll let the engineers fight out the effects of EM fields on optical fiber transmissions. I suspect that, each in their own way, both of the posters above are right. Empirically, I stand by my statement that in *my* studio, standard Toslink short-run cables do not receive any audible or visible interference from being run in close conjunction with 120V-AC 20 amp power cables. Therefore, whether this results from "resistance" or "immunity" is not particularly relevent to me. Use the nice Toslink cable and be happy for about $5. Or- you can pay $30 or so for a Canare coaxial cable and try to figure out how to keep it away from transformers and power bearing cables. Whatever floats your boat.-Richie
 
Even if there is a theoretical effect on the light-based data stream (and that would be a level of Einsteinian particle physics way above my pay grade) it's just that: theoretical. High quality fibre optic cables are literally thin tubes of glass (i.e. the best natural insulator around) carrying some form of light, be it visible or in the IR or UV spectrum. Light is able to be bent by gravity--but gravity is different from EM or RF radiation. The reality is that signals, be they data or audio encoded as data, can travel many thousands of miles through fibre optics and arrive at the other end unaffected by any external interference.

Even if cheap TOSLINK cables are plastic, not glass with a maximum range of 20 feet or so, there is not a problem with EMI for RFI in any practical sense.

In my previous post I speculated that if there is any interference issue at all, it's far more likely to be in the electronics at either end than in the cable itself. However, these electronics are largely common whether you're using coax or fibre.

I remain a total sceptic that the fibre itself can in any way be affected by EMI or RFI but would be very curious as to what your father in law has to say on the topic if you can persuade him to post. However, for the time being, I'm happy to continue in my belief that light--and glass or plastic--cannot in any way be affected by EM or RF interference.
 
Bobbsy said:
The reality is that signals, be they data or audio encoded as data, can travel many thousands of miles through fibre optics and arrive at the other end unaffected by any external interference.
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Don't take my word for it, talk to people who lay fiberoptic mains cables for infrastructure and look at all the things to do to protect signal integrity when it passes under major power lines. Do more research instead of simply saying you are skeptical. With all do respect, When I don't know something, I try to find out the answers rather than get into pissing contests. This might be a great opportunity to actually learn something few sheeple know.

I remain a total sceptic that the fibre itself can in any way be affected by EMI or RFI but would be very curious as to what your father in law has to say on the topic if you can persuade him to post. However, for the time being, I'm happy to continue in my belief that light--and glass or plastic--cannot in any way be affected by EM or RF interference.
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So now you need a third party to convince you? Dude- google is at your fingertips. I can't BELIEVE I'm having a pissing match with someone who thinks magnetic fields won't go RIGHT THROUGH plastic or glass. Seriously!? Granted, the purest forms of glass (see my earlier posts about AT+T glass quality and how it is an extreme exception) will block electromagnetic fields, but such glass is rare and expensive in the world of fiberoptic cable. MOST glass has impurities...mostly METAL impurities. Any idea what magnetic fields do to metal?(Look it up if you aren't sure.) Metal also makes a wonderful antennae for radio waves!

All of this is concerning the glass only, which I assure you if of the cheapest (impure) quality in you average Toslink cable. This is only the beginning, there's a lot more to a cable than just the glass...
This is over as far as I'm concerned. You get the last word.
 
Since YOU started the pissing contest, let's have one.

Prior to my retirement, I was Vice President, Operations and Engineering for a large London-based television news organisation. We HAD a large network of fbre optic cables and I did talk to the people that installed them. I even had the scrap end of one of the multiway fbres that entered our building. Those fibre optic cables are heavily protected against physical damage (for example kevlar wrapping around individual strands and more around the bundle) but there is no special protection against EMI and RFI--because there is no problem.

You mention metal impurities in the fibres themselves. There are, indeed, standards for the quality of the fibre for long distance runs--but even in this case, such impurities can cause physical failure of the fibre itself, NOT interference in the signal being carried. The light (in the case of long distance fibres it would be invisible laser light) is not affected by the EMI or RFI and, unless the path is physically broken, will give interference free reception at the far end.

In any case, this topic was about the choice of coax or TOSLINK for a short interconnect in a home studio. As I said much earlier, either should work just fine. Over the distances we're talking even coax is highly resistant to electrical or RF interference...while fibre is totally immune. However, this distinction is like debating how many angels can fit on the head of a pin. Pointless.
 
Bobbsy said:
Since YOU started the pissing contest, let's have one.

Prior to my retirement, I was Vice President, Operations and Engineering for a large London-based television news organisation. We HAD a large network of fbre optic cables and I did talk to the people that installed them. I even had the scrap end of one of the multiway fbres that entered our building. Those fibre optic cables are heavily protected against physical damage (for example kevlar wrapping around individual strands and more around the bundle) but there is no special protection against EMI and RFI--because there is no problem.

You mention metal impurities in the fibres themselves. There are, indeed, standards for the quality of the fibre for long distance runs--but even in this case, such impurities can cause physical failure of the fibre itself, NOT interference in the signal being carried. The light (in the case of long distance fibres it would be invisible laser light) is not affected by the EMI or RFI and, unless the path is physically broken, will give interference free reception at the far end.

In any case, this topic was about the choice of coax or TOSLINK for a short interconnect in a home studio. As I said much earlier, either should work just fine. Over the distances we're talking even coax is highly resistant to electrical or RF interference...while fibre is totally immune. However, this distinction is like debating how many angels can fit on the head of a pin. Pointless.
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Sorry I can't leave this alone- it's too easy. Could your all out IGNORANCE regarding the properties of plastic and fiberoptics in general have anything to do with your 'retirement' as vice president of 'operations and engineering'? After all, a common third grader would know electromagnetic fields can pass through plastic!! You must have been quite the 'engineer'....or maybe you were just head of the engineers? Hmm?

As it turns out, THIS WEEK (not eons ago when you were VP of Antiquated, Inc.) workers are laying a fiberoptic main right down MY street, and they were right outside MY front door in MY yard digging trenches under the power lines ( FiberCo. Howard County. Project for Verizon and the Miller branch Library. Ellicott City. Maryland. Frederick road) It sure was amazing listening to them, and watching them waste all of that money on shielding. I guess they should have had you for a boss, eh? You coulda taught them tons of stuff and saved Howard county tons of dough...all without you actually possessing any actual knowledge, of course.

Piss off. Let's stay clear of each other on this forum.
 
When you can provide one scientific or engineering document explaining how magnetism or radio waves can affect light, please post it.

Otherwise, take your pseudo scientific, unattributed layman's knowledge and YOU piss off--and stop giving poor beginners bad advice such as "a TOSLINK cable is still affected by EMI and RFI"...including a link that actually contradicts the point you were trying to make.

When you've managed a worldwide network of fibre (and satellite) communications come back and talk. Otherwise stick to your amateur home recording.

You piss off--and the next time you give wrong and inaccurate advice, I'll call you on that as well.
 
Bobbsy said:
When you can provide one scientific or engineering document explaining how magnetism or radio waves can affect light, please post it.

Otherwise, take your pseudo scientific, unattributed layman's knowledge and YOU piss off--and stop giving poor beginners bad advice such as "a TOSLINK cable is still affected by EMI and RFI"...including a link that actually contradicts the point you were trying to make.

When you've managed a worldwide network of fibre (and satellite) communications come back and talk. Otherwise stick to your amateur home recording.

You piss off--and the next time you give wrong and inaccurate advice, I'll call you on that as well.
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You have issues. Let's review the facts and catch everyone up [(including you) though I doubt it makes any difference seeing how your head is so far jammed up there you cannot possibly be reasoned with.]

OP (and others) mention Toslink cables and their so called immunity to electromagnetic fields. To which I say they are not totally immune. Extremely resistant? Yes, indeed.

I find the first white paper I can on the subject and they say such cables are (and I quote) "RESISTANT" to EMF. Later on in the paper you find them as saying fiberoptics are immune to EMF, and you cite this as counter proof.

Let me dumb this down so that you can understand it in the real world, seeing how that's how most "professionals" need it given to them:

A Toslink cable is NOT pure light. You keep hammering on this notion that we are talking about pure light and it's data integrity. We are not. Since the rest of us are talking about the finished product and how it compares to coax, let's stay on point, shall we? The light is only one part of a finished product. A Toslink cable is made up of lots of stuff- all of which are vulnerable to electromagnetic fields. Now is that light an awesome medium for transmitting data without electromagnetic interference? Hell yes. No one is arguing that (except you). As I keep trying to steer you on- consider how the cable is manufactured and what goes into it. The yarns and strengthening agents that allow you bend the glass easily are vulnerable to EMF. The shielding of a typical Toslink cable is vulnerable to EMF. The plastic used is vulnerable to EMF. Even the glass itself with it's impurities containing metal particles are not only vulnerable to EMF- they can act as conductors to it and RFI.

So what does this mean? Consider the little emitter and receiver that you plug your Toslink cable into. It's getting this lovely data from the light part, but ALONG with that it's getting trace amounts of electromagnetic and radio interference. In short a Toslink cable (as an entire finished product) is technically NOT COMPLETELY IMMUNE.

pure white light? Immune. You'll even find the term in many white papers (for investor/marketing purposes).

manufactured fiberoptic cable system? NOT totally immune. Some (not all) white papers are careful to say "highly resistant" when referring to the finished product.





Look at that white paper again and read it closely. Perhaps it isn't the best one I can find but notice they say both
 
You are clearly an idiot and a troll.

A TOSLINK cable is a lump of two pieces of plastic--a clear inner covered in a protective outer. I carries the red light from a flickering LED which is modulated to send data.

Neither plastic nor light is affected in any way by magnetism or radio frequencies. This means that TOSLINK cables are immune to EMI and RFI.

If you're talking high end fibres with "yarns and strengthening agents" then it's possible that these could be affected by an immensely strong EM field--but, until that effect is enough to physically break the fibre, the light is still being transmitted and will result in a perfect signal at the receive end.

Fuss and bluster all you want. You said that TOSLINK cables can be affected by EMI. That's bullshit. If you change your story and say that the equipment at either end of the fibre can be affected by EMI and RFI, that's obviously true. Any piece of electronics can be affected if the fields are strong enough. But that is NOT the same thing as the TOSLINK cable being affected by the interference.

In post number six of this thread you said that TOSLINK cables are vulnerable to EM but not RF. When you were called on this you started with some techno babble to justify your wrong statement. Now you won't let it drop even though you are clearly and patently wrong. When I gave my credentials to discuss this you turned to personal insults.

You're a fuckwit and a troll. I'm done. People can make up their own minds about the rubbish you're posting.
 
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