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Optical or Coaxial?

Discussion in 'AV Receivers & Amplifiers' started by weyland-yutani, Aug 23, 2003.

  1. weyland-yutani

    weyland-yutani
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    To connect DVD player to amp, which is best, is there even a difference?

    :confused: :)
     
  2. owenw

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    Coax is better for any digital audio connections.

    Optical is a cheapo option used my manufacturers to cut the cost of building AV components.

    Owen
     
  3. alexs2

    alexs2
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    This one has been answered many times and provokes a lot of support from both sides....as Owen says,broadly speaking,coax is capable of potentially better results.....whether or not you notice it is down to the quality of the components you are using....some simply aren't capable of resolving any difference.
     
  4. Smurfin

    Smurfin
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    :rolleyes:

    You'll notice no difference frankly.
     
  5. buns

    buns
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    When photonic bandgap technology trickles to optical fibres, they will be a far more efficient transmission medium than coax..... anybody arguing simply doesnt understand photonic crystals! :p

    Of course this still will include an additional conversion between optical and electrical which may negate the benefits of the bandgap fibre. But then again, optical signal processing is now possible, it is very likely that devices originating in the optical sense will at some stage become all optical and the coaxial connection will be a poor cousin!

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  6. Smurfin

    Smurfin
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    ahh but what about the transcendental coaxial reflex signal, which surely negates any need for the optical fibre, although that said once the reflex signal kicks in its simply converted to an optical signal which thus renders the whole argument a bit moot, and the fact is if you've read all of what I've just typed means you have the patience of a saint or you're just plain sad. Go figure.
     
  7. alexs2

    alexs2
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    Hopefully after that,weyland should be able to get what he was asking from owenw's post....if he has both optical and coax cables available,the easiest way is simply to try both....if one sounds better...stick with that.
     
  8. owenw

    owenw
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    buns and smurfin: were you two employed by the Wachowski Brothers to embellish the script for The Architect in Matrix: Reloaded by any chance?! LMAO :D
     
  9. Smurfin

    Smurfin
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  10. buns

    buns
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    Who said it's a script?
     
  11. rozzar

    rozzar
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    its cheaper to get a decent digital coaxial cable (e.g. Black Rhodium Rhythm silver plated digital £15) than a decent optical (Black Rhodium Silver Grey £30) Coaxial also runs at a stable 75ohm signal, which optical doesn't. imho coaxial sounds much more natural than optical.
     
  12. buns

    buns
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    impedence doesnt have much meaning in optical terms..... refractive index and such likes replaces thjat

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  13. weyland-yutani

    weyland-yutani
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    I think I'll go with the coax. thanks for the imput, guys:)
     
  14. Nic Rhodes

    Nic Rhodes
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    I like that :) It is a pity that virtually EVERY coax doesn't run at anything near 75 ohm and this is completely irrelevant for optical! I won't even mention RCAs.....;)
     
  15. mjn

    mjn
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    didn't know it was April 1st.....
     
  16. Prav

    Prav
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    In layman terms doesn't the optical have to convert the 'light' signal into an electrical one, that coaxial uses in the first place. Therefore coaxial is a bit more pure. Or have I missed the point.
     
  17. buns

    buns
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    i presume that electrical is converted to optical for the optical connection (by the device of course, not the cable). But, dont forget there has already been a conversion from optical to electrical since the disc is read in an optical fashion..... hence we need optical SP :D and then we can forget coax electrical altogether!

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  18. mjn

    mjn
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    c0-ax can be prone to electrical interferance though......anyway, do a search this topic has been discussed many a time before!
     
  19. Sunday Ironfoot

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    Sorry, but I fail to understand how there can be a difference since in both instances the signal is being transmitted digitally, the noughts and one's are either there or they're not. Doesn't the receiver simply re-request data that's missing, similar to how 'packet loss' works over an internet connection?
     
  20. buns

    buns
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    well the signal processing in a player is done electrically, optical processing is bleeding edge stuff that will be a while before it makes it to this level. So the signal exiting the player is natulally electical in nature. So to use optical you need to convert it to optical, which is a potential source of error. Then, in transmission, both routes are subject to loss by interference, loss though a cable when reflection conditions arent met, that sort of thing. There theoretically is error correction, but this is not full proof

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  21. thackl

    thackl
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    Hi guys,

    Optical systems can introduce additional jitter because the signal is converted from electrical pulses to light pulses and back again.

    here is the theory I found on http://www.htcentral.net

    Quote:
    "With digital data, there are only 2 considerations, data integrity and timing. If cable distortion or interference or whatever causes the 1 or 0 to be incorrectly received, then the data integrity is lost and you get a gross error (dropout or a pop). If the 1 or 0 is correctly received, there can still be an issue with the timing of the data. With PCM, the timing clock for the DAC conversion is usually recovered from the transitions in the data signal so variations in the incoming clock signal will subtly distort the output waveform. This timing error is commonly called jitter.

    Jitter can be introduced as the data is read and extracted from the DVD (or CD or whatever). With a poor cable it is also possible that distortion or interference may alter the shape of the data signal enough that the transitions are detected by the receievr at the wrong time, adding additional jitter.

    With DD, dts and MLP (I don't know enough about DSD) the data streams are buffered and decoded with a separate clock (which may still be slaved to the incoming signal but will vary less due to the buffering) as these formats compress the data. In this case, the effect of the jitter in the incoming data stream on the output waveform will be far less."

    Here you'll find what happened to a Steely Dan master

    http://www.rogernichols.com/EQ/EQ_2000_02.html

    and here you can find everything about jitter
    http://www.geocities.com/jonrisch/jitter.htm

    Cheers
    Tom
     
  22. buns

    buns
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    But dont forget we are already accepting an optical to electrical conversion without any arguement, the jitter that such a conversion adds must be small else we should be moaning about the first conversion!!

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  23. Ian J

    Ian J
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    This was discussed about 18 months ago in a very long and heated thread which by the end had resulted in several members becoming guests.

    I can't find the link now unfortunately
     
  24. buns

    buns
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    But..... the discussion has advanced....... there have been remarkable advances in photonics over the last couple of years.

    I suspect that thread is gone..... was it not a little bit nasty?

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  25. MattB

    MattB
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    Hey thackl, thanks for the Roger Nichols link I enjoyed it immensely and own a copy of the CD in question...

    Re- the optical vs coax debate, I use coax within my hifi for minimum jitter and optical between PC and hifi. Why optical? I don't give 2 sh!ts what the jitter is in this connection but I do like to have galvanic isolation between the electrically noisy PC and quiet oasis that is my hifi.

    p.s.
    Arcam owners may not benefit from the electrical isolating properties of an optical connection since their gear is riddled with switch mode power supplies anyway. (the enemy within)
     
  26. buns

    buns
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    Oh nobody get me wrong...... id be far more keen to debate the future than the present...... the comparison really isnt fair to make.

    MattB,
    nice thinking on the optical! never considered that myself! Not sure the arcam owners will appreciate though! :D

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  27. MattB

    MattB
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    :devil:
     
  28. Chester

    Chester
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    No. Digital audio transport is one way only, unlike TCP/IP over Ethernet, which would be pretty useless if it was one way, wouldn't it!?! ;) A separate cable would be required to pass audio or control data back the other way.

    Just to join in the Coax Vs. TOSLink debate, has anyone actually tried swapping over from one to the other to observe the effects? I tried it some years ago with an audio CD and a Wharfedale DVD-750 (all I could afford at the time) as the source and didn't notice any difference at all.

    I'll also add that anyone who believes there is a difference in sound quality with an encoded audio signal (such as Dolby Digital or DTS soundtracks) is gravely mistaken. A temporary loss of data down to any small degree is extremely noticeable with large amounts of audio artifacts that are rather loud and bite at your ear drums! Anyone who has experienced a cable not being plugged in correctly or a cable breakdown will know exactly what I'm talking about.

    However, this is not true of CD audio. The way that digital data works for CD audio infuriates me. You can hear differences with different cables for CDA. Why something hasn't been invented to ensure that 100% of the CDA's details have been passed to the DAC at all times is beyond me.
     
  29. GAmbrose

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    Quite frankly, anyone who thinks they can hear a difference between the 2 cables is either the bastard child of Batfink and Superman or simply deluding themselves.

    Gary A
     
  30. Craig Summers

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