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optical vs. coaxial digital input

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airwalk

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It's commonly known that electrical S/PDIF (i.e. Coaxial) is better than it's Toslink (i.e. Optical) sibling.

Toshiba apparently didn't give Toslink that much bandwidth, so that's the whole thing right there--a coaxial connection has higher theoretical bandwidth (though it's quite arguable/argued whether that's important for any of the uses we have for these interfaces anyway).

However, where coaxial connections are subject to EMI/RFI interference, ground loops, etc. in the cabling, Toslink is impervious to such degratation/alteration of the signal through it's cabling. Optical cables, OTOH, are susceptible to what people call "jitter"...

Technically, if we're just talking about the signal transmission with no external variables, coaxial is the "better" connection without a doubt. Note however that you'll never hear a difference between the two unless something is seriously wrong with the connection/cabling/equipment to make something different about the sound. There are people (usually so-called audiophiles) that "pooh-pooh" optical connections claiming some kind of huge noticeable differences in sound. Pure nonsense if you ask me--it's mainly in their heads in that they know coax. is technically better therefore it must sound better :rolleyes:

As for why they didn't use a miniplug version of coax. S/PDIF, I'm not sure about that. Could be a variety of reasons, perhaps stemming from the "coolness factor" optical cables have (or at least used to have) to the fact that some people might use cheap cables (non 75-ohm) of questionable quality, to make the connection. Toslink cables on the other hand, at least at the time, were at least of good/consistent quality.

In any case, it's the way it is and given the roadmap/lifespan of both optical and electrical S/PDIF is near the end (as well as MD for that matter, lol), it's safe to say there never will be a miniplug version of coax. S/PDIF.

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As for why they didn't use a miniplug version of coax. S/PDIF, I'm not sure about that. Could be a variety of reasons, perhaps stemming from the "coolness factor" optical cables have (or at least used to have) to the fact that some people might use cheap cables (non 75-ohm) of questionable quality, to make the connection. Toslink cables on the other hand, at least at the time, were at least of good/consistent quality.

In any case, it's the way it is and given the roadmap/lifespan of both optical and electrical S/PDIF is near the end (as well as MD for that matter, lol), it's safe to say there never will be a miniplug version of coax. S/PDIF.

Thank you a lot for in-depth explanation of S/PDIF differences.

Optical is cheaper to add, costs almost nothing

That's questionable. Why do you think it's cheaper? I dunno about exact schematics but it looks for me it's easier to attach a miniplug instead of optical transcevier since the output coding (channel level, iso/osi) is the same.

The question I asked stems simply from the fact that it's more common to see coaxial s/pdif on the pc audiocard instead of optical. So one need either to buy an appropriate sound card or a custom-made transceiver (which is rare in many countries).

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The block the optical plug fits into is cheap, look up prices on the 'net. It is all plastic (coax requires metal) and the optical receiver is just a single solid state device built right into the plastic jack. Solders right onto the board and your done. It requires no ground connection, one less connection to make.

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The block the optical plug fits into is cheap, look up prices on the 'net. It is all plastic (coax requires metal) and the optical receiver is just a single solid state device built right into the plastic jack. Solders right onto the board and your done. It requires no ground connection, one less connection to make.

You're correct there, but you're forgetting that on MD portables, this is not the case. This is beacuse that jack is used for both analog line in (which requires the metal contacts) and the optical connection.

However that^ could bring another explanation. It saves space this way. You have analog line input and digital input all in the same jack.

Perhaps you could have electical S/PDIF but then you'd have to switch something in the menu/software on the player in order to switch between the types. I wonder what kind of awful noise you'd get if you accidentally recorded a digital signal as if it were an analog one? Perhaps to avoid that situation, and to save space, the optical connection was preferred.

What would be really quite cool would be a three-in-one input--one having switchable analog line, coax. digital as well as optical all in one jack! However again, it's not going to happen, lol.

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Philips used just such a connector on its DCC portable (Dcc170 and 175). For analog or optical use, you used cables that we are familiar with. For COAX input you had a special cable that had an extra ring on the end. When plugged into the jack, it was sensed as the COAXIAL cable. Incidentially, they had the same setup on output. It would output analog, optical or COAXIAL signals

Yes, I know you have metal for the analog section, but you would need seperate contacts for COAX since they would go to different circuitry for processing.

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