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Digital Coaxial SPDIF from PC to Receiver...Interference...new wire or go optical?

Discussion in 'Desktop & Laptop Computers Forum' started by echoniner, Aug 3, 2005.

  1. echoniner

    echoniner
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    Hi all, my first post here:

    My stuff: I have a Digital Coaxial SPDIF on my ASUS Motherboard in my PC, ran by nVidia nForce2 audio drivers and capable of 5.1 sound. My MoBo does NOT have an optical digital SPDIF (Tosc link). My Coaxial cable is a no-name brand, and it connects my PC to a Yamaha RX-V1500 A/V Receiver/Decoder (a high-quality receiver).

    My problem: When playing MP3s and the like on my PC thru my receiver, it seems that there is lots of interference. For example, I can change the speed of my ceiling fan or turn the light on or off in my bathroom and have the audio cut out momentarily as I do so. Concerned that it might be the motherboard, I connected my set-top DVD player via the same Coaxial cable and played a CD...sure enough, same electrical changes in the apartment would cut the audio out momentarily. However, when I play a CD in my DVD player thru the Optical Tosc link, no interference whatsoever. I did some other tests w/ high-end monster video cables acting in the place of the audio SPDIF coaxial and they were not suspectible to the same interference.

    So: Clearly, my SPDIF Coaxial Digital cable sucks. I have 2 choices now, and this is where I ask what is best to do:

    A) By a high-end Monster Cable THX-certified SPDIF Coaxial cable, which I need about 6' of, so roughly $80 or so. This apparently would fix my problem 100%.

    B) By a PCI sound card that will give me a Optical SPDIF Tosc link and then buy a 6' fiber cable, costing me probably closer to $200 total.

    1) The real question here is: which should I do and why?

    2) Is there any added benefit of the optical over the coaxial, particularly when the primary purpose of having my PC connect this way is MP3s which are inherently noisey to some extent? (Of course the optical might be nice for future or less often used features like PC gaming.)

    3) Will a high-end SPDIF Coaxial cable still be suseptible to some degree of interference?

    4) Finally, Soundblaster, with their damn monopoly, doesn't offer ANY soundcards with the optical connection unless you go to their solutions requiring two PCI slots or one PCI slot and one CD Drive Bay or external solutions that connect thru USB...Soundblaster clearly doesn't know the market, and I wish a new kick-butt competitor would serve my needs. Anyhow...I'd prefer an all-in-one PCI solution for the optical if I go that way...suggestions? Should I just do the external USB SoundBlaster option?

    Sorry for the long post, but thank you for your comments. The consensus of the responses will determine my course of action. I hope to fix this asap...

    Thanks!
     
  2. DaveP

    DaveP
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    You should not get interference even if you are using a budget cable. If I were in your situation I think I'd buy a reasonable priced cable and try that. I personally think Monster cables are over priced.

    There may be a third option for you: Some Asus boards have the option to connect an accessory: Asus Optical and S/PDIF Connector which is what I use. Check your mobo manual to see if you can use it with yours.

    If you are only going to use the sound card for digital output you really don't need to spend a lot of money on a SoundBlaster as it will be just passing the digital signal through, and not processing it at all.

    Dave
     
  3. echoniner

    echoniner
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    I have the ASUS A7N8X Deluxe (Rev 2.0) mobo, and it does seem there is an optional SPDIF connector. However, it seems, from what I can judge from the manual's limited picture of this item, that it just another coaxial digital SPDIF connection. I'll try to find it on their site and see what the options might be...
     
  4. Big Adam

    Big Adam
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  5. Dillz

    Dillz
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    If it helps I have the same motherboard as you and bought this cable from tvcables.co.uk, and get no interference at all;

    http://www.tvcables.co.uk/cgi-bin/tvcables/PGD485.html

    I did have to make the hole around the socket a bit bigger though as the plug on the profigold lead is rather chunky.

    Incidentally do you have a decent PSU, being as your problems seem to be electrical interference.

    BIG_ADAM do you know if that fits the ASUS A7N8X-E ?
     
  6. rdhir

    rdhir
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    Your cheapo cable is probably so cheapo it is not shielded, hence the interference.

    Generally Hi Fi people say stick to electrical that is Digital Coax over optical as over short runs (less than 5m) There is no benefit to optical. In fact as the signal has to be shifted from electrical to optical and back then there is no real point in switching at all as there is just additional loss in conversion. (This is due to digital jitter which I won't go in to here - lets just say there is a slight timing variance, even though the signal arrives with the correct value).

    I agree that there is not point in expensive Monster cables, Profigold do a very reasonable one at £20 available almost anywhere in the UK. Not sure where you are but I suggest that a budget of $30USD/30Euros/£20 is more than enough.

    Cheers Rajiv
     
  7. echoniner

    echoniner
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    My PSU is a premium Antec 400W supply, plus my PC is plugged in to a Belkin UPS with voltage "cleaning" or regulation, so I'd be very surprised if I have power problems.

    That ASUS adapter is nice...simply because it adds the optical, but it sounds like by using optical I'd not get any benefit? It does seem from my trial and error that optical works better than coaxial in terms of not being affect by interference, but I might be comparing apples to oranges since the optical cable is a premium one and the coaxial clearly is a crappy one... It seems as if that company doesn't ship to the US, but I'm sure a local vendor would have it. I know my board has the SPDIF internal connection which would allow this adaptor... Anyhow...we have at least one vote that says optical won't help me any, so should I just get the better cable then and not get this piece?

    Otherwise I'm tempted to just go to the local electronics store and buy a non-Monster premium cable...

    Thanks for all of the feedback so far!
     
  8. echoniner

    echoniner
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    Ah, these adapters are available... ebay.com has 'em for "buy it now" prices of just under US$5.00 + US$2.00 S/H.

    So at such a cheap price, perhaps my question should be restated: since I am definitely going to buy a new cable, should I buy a coaxial or optical SPDIF, considering the optical one will only cost $7 extra for the card, or is it not worth it? (Of course I give up a PCI slot on my case with this adaptor too, and if no value added, why?)

    Derek
    Location: Ohio, US
     
  9. Son of Shaft

    Son of Shaft
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    it's possible the noise comes from a ground loop, using optical is the easiest way to get rid of it.
     
  10. dazzer123

    dazzer123
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    I believe i may have had exactly the same problem and after spending a fortune on sound cards and alike and solving nothing i found a very simple and cost free solution,i had sound drop outs mainly on dts and 5.1 audio these were the most noticeable problems although there was slight video stutter although practically unnoticeable as the audio drop out was so bad maybe just maybe the same solution could work for you.

    Basically my problem came down to my hard drive i had built a very well specd p4 based system and in the end this very well specd system was struggling to do the simplest thing playback a dvd with out dropping sound every few seconds.

    My hard drive was an ide model a maxtor ata 133
    and after trying different sound cards and video cards i found that if i went into device manager and whilst there click on disk drives and when in there click on your hard drive model ie: maxtor 6y120po then you get a box with four tabs at the top general, polices, volume etc etc click on polices in there is an option called enable write caching on the disk,this will most likely be selected if so unselect this option and then try to play back a dvd with dts or 5.1.

    if it cures your problem great if not you can go back reselect enable write caching write caching does improve hdd performance generally but in my case for playback of dvds made things very difficult the problem i had apparently is very common and yours sounds similar but the answer can be difficult to come across i hope your problem is the same and this is of some use to you good luck. I still run the maxtor but now with a sata along side which has solved my problems.
     
  11. echoniner

    echoniner
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    So it turns out that if I were to buy the ASUS adapter, it comes w/ a 4-pin wire that I connect the adapter to the motherboard's SPDIF pins. The 4 pin is in this wire is in this configuration:

    X X X X

    However, my board expects a 6 pin SPDIF connection:

    X X X
    X X X

    Now, if I individually wire the necessary pins, this will work, this I am sure of. (Mine has 6 to allow a SPDIF in and out, and I just won't have SPDIF in.) These wires often come as individual wire pin connections with the board, but the ones that come with the board are used for the LED light, the HDD Activitiy light, etc.

    So, my question is: where I can I find individual pin wires? I don't know what their proprer name is, so I can't find 'em online.

    Thanks,
    Derek
     
  12. echoniner

    echoniner
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    Just to finalize this thread, I did get the adapter from ebay (same one shown/recommended in this thread) for about $5, jimmy-rigged the cable connection to the motherboard by matching pin-by-pin (see post above) the right pins as required using the necessary cables I picked up at a local privately-owned computer place for $1, then I connected this to my A/V receiver via a new $30 THX-certified 2m Monster Optical cable. Audio sounds great, and more importantly, I can flip any electrical switch on or off in my house and get no interference! Total cost ~= $36.

    Thanks to all for the inputs!

    READ ON FOR DETAILS ON HOW TO JIMMY RIG THE CONNECTION IF INTERESTED:

    For those interested in how to jimmy-rig this connection, ask your computer store for cables to connect a motherboard to case LED lights or the reset or power buttons on the case. You may have to do some cutting and splicing of the wires depending on what you get, just don't cut near the actual connector because you'll have a heck of a time trying to splice near there, and removing/replacing the connectors onto the wires isn't straightforward. Anyhow, for my ASUS board, I have a 6-pin config (see attachments), and the adapter on ebay had 4-pin. You'll have to give up the SPDIF Input capability of this board to use this adapter (the mobo supports this, but the adapter with optical doesn't), but who cares. Most of us have no use for this anyhow. Anyhow, match the +5V, one of the grounds (either), and the SPDIF outs and you'll be golden.
     

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  13. james.miller

    james.miller
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    so it was a ground issue after all then....glad you got it sorted:)
     

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