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toslink cables -- minimum quality required?

Discussion in 'Sound, Music, and Intercom' started by jkowtko, Jan 22, 2008.

  1. jkowtko

    jkowtko Active Member

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    I'm looking for some 12 to 25 ft toslink cables to connect the ADA8000s to my 01v96 mixer. Question -- is quality an issue here or will any $5 cable work fine?

    At home I use Belkin PureAV blue (~$12 each mail order) for the DVD player and I get a very good Dolby Digital sound out of it. But I've seen cables for as cheap as $3 each.

    Any advice on this? Should I get someting equivalent to the Belkins or will cheaper cables work just as well?

    Thanks. John
     
  2. mbenonis

    mbenonis Wireless Guy Administrator

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    IMO fiber is fiber. I'd imagine that as long as the light can be transmitted well enough the cable ought to work fine. You don't have the same issues as with copper cables, such as noise, interference, etc.
     
  3. Dillon

    Dillon Active Member

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    Mike is absolutely right. No optical (or any other type of digital cable) is different than any other, sonically speaking that is. Some may stand up to wear and tear better than others, depending on the jacketing. The same goes for HDMI, ethernet, and any other digital transmission cable.

    This stems from the fact that all digital information is transmitted as either a zero or a one. For analog signals, the value can be anywhere in a range of voltages. When the digital value is transmitted along the line, no external interference can change that value, as can happen with analog signals.
     
  4. mbenonis

    mbenonis Wireless Guy Administrator

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    I'd like to qualify this statement slightly - due to the large voltage thresholds for the 0 and 1 values (any voltage between +4 and +5V, for instance, is a one), coupled with good error correction in today's electronic equipment, it is very uncommon for a digital signal to become unusable due to noise. But it CAN happen if you try hard enough. It is important to remember that the real world is analog, and those ones and zeroes are still voltages on a line.

    (Dillon, I certainly don't mean that you're wrong - I just want to remind folks that digital isn't a magic bullet. :) ).
     
  5. derekleffew

    derekleffew Resident Curmudgeon Senior Team Premium Member

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    Even with optical cable?
     
  6. Chris15

    Chris15 CBMod CB Mods Premium Member

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    Well yes and no... They are ones and zeros on a PCB track before the transmitter and after the receiver... :mrgreen:
     
  7. cutlunch

    cutlunch Active Member

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    In this case either of the cables you mentioned should be suitable.
    But like anything else there are different types and grades of fibre optics. Certain types allow faster transmission speeds with lower loss per unit length. If this was fibre optic cable for a computer network then you have to take the fibre quality into account.

    For audio if it's only a few feet then both cables should work as well.
     
  8. SHARYNF

    SHARYNF Well-Known Member

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    Look for a reasonable quality in the connector, and the quality in the casing It is not so much the actual fiber but the bits and pieces around it
    Sharyn
     
  9. jkowtko

    jkowtko Active Member

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    I had read in the Belkin marketing literature (marketing, of course!) that cheaper quality fiber could potentially drop bits if the light intensity doesn't come through strongly enough ... it sounds like that not a real issue (does the ADAT protocol have error correction in it?) other than general construction quality of the cables. Okay, I have the opportunity to buy some cheapo cables locally -- I might try a couple of those first, then move to better quality if these cause problems.
    Thanks. John
     
  10. Chris15

    Chris15 CBMod CB Mods Premium Member

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    The reality is with fibre there a couple of things to consider generally...
    No 1 is single mode or multimode - will be determined by the laser in the transmitters.
    But given we're talking Toslink here, it's just an LED so I suspect strictly it's neither of the above...

    No 2 is the diameter of the fibre - 50um is about normal for multimode and 7 or 9 um for single mode.

    But in reality, the thing which will change things most and this one does apply for domestic fibre as well, is the terminations. Fibre = painful to terminate because of the size and because you have to get an absolutely flat and dust free surface or the light does not reflect properly and you get big issues...
    So even with domestic fibre, which is what I'm using to describe toslink etc., keep your connectors clean and follow the instructions to clean them if need be. There is a reason touring fibre systems come with attached dust caps and the first thing you do after disconnecting the fibre is to screw in the dust cap...

    I suspect that the Belden guff is scare tactic to get you to buy their more expensive product... And you're only talking a few metres not a few km so I suspect it shouldn't be too much of a issue...
     
  11. mbenonis

    mbenonis Wireless Guy Administrator

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    Yep. At the end of the day, you're still taking digital bits and modulating them onto an analog carrier (in this case, a beam of light). In fact, light is just really really high frequency EM radiation. The benefit to using optical, of course, is that because of the high frequency of the signal, it's impervious to traditional noise sources.
     
  12. jkowtko

    jkowtko Active Member

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    Fyi, I bought a set of cheap cables, checked them out at home with two ADA8000s fully connected, and they sounded fine to me -- but with only a few channels active with audio signal.

    However they are pretty flimsy ... no protection around the cable at all, and I'm afraid to get anywhere near them for fear of kinking or breaking them ... so for my own comfort I will probably buy some beefier ones for production use. I can still get 5mm or 8mm thick cable with metal ends for $5-8 each, so for the small investment it's probably worth the peace of mind.
     

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