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What causes low level hum from audio chipset?

Discussion in 'General Hardware' started by twilyth, Jun 19, 2011.

  1. hat

    hat Maximum Overclocker

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    So you have two screens? Your 5850 should have 2 video outputs for that. I'm talking about using the onboard hdmi out and piping that to your receiver. Your onboard audio drivers might have provisioning to use that. You could also try using that onboard s/pdif header. The output on the expansion bracket would look like this (far left)

    [​IMG]

    And this is the cable you would use to connect them: coaxial s/pdif cable (it does deceptively look like an analog RCA cable, but it isn't quite that)

    [​IMG]
     
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  2. twilyth Guest

    OK, I just had a flash of motivation and connected the stereo out from the tv to one of the AV inputs and there is now almost no hum.

    I noticed that the tv also has optical audio out, so just for yuks, I might get a toslink cable and patch that to one of optical inputs.

    However I am still intrigued by using the spdif header to an RCA jack and running a cable to one of the orange input jacks.

    Thanks again to everyone for you help. I appreciate it. :toast: :toast:
     
  3. hat

    hat Maximum Overclocker

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    As long as you got it working how you want...
     
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  4. twilyth Guest

    I was under the impression that you couldn't have 2 different video chipsets enabled at one time except for SLI/Crossfire.

    Unless you're saying that I can somehow just enable the audio portion of the onboard chipset. IDK. I could be completely missing the point you're making. :toast:
     
  5. streetfighter 2

    streetfighter 2 New Member

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    If you don't already have an RCA cable that would work lying around, then just buy a TOSLINK cable because it's optical and therefore not susceptible to interference like an electrical cable is.
     
  6. hat

    hat Maximum Overclocker

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    I really have no idea, it's just a long shot in the dark I'm playing with here. To use that onboard HDMI in the fashion I'm thinking of, you shouldn't need the onboard video enabled, just the audio. As long as the onboard audio has provisioning to use that (I'm not sure if it does), audio over that HDMI should work whether the onboard video is enabled or not.
     
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  7. twilyth Guest

    Yes. That makes more sense since the brackets seem to have both. It's just that I'll need a long cable - 4m about - due to the placement of the AV rack and the HTPC. :toast:
     
  8. twilyth Guest

    I think the audio and video on the HDMI output are a package. I think if you disable one part you disable everything. If you could still somehow access the audio even when disabled, then we might be on to something, but I'm pretty sure that's not an option.
     
  9. BumbleBee

    BumbleBee

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  10. Jetster

    Jetster

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    Thats how mine is toslink from tv to reciever. The only downside is its not True 5.1 as most TV wont passthru True 5.1. At least thats what the Audio Tech told me when I set mine up. So you end up with Dolby ProLogic 5.1
     
  11. hat

    hat Maximum Overclocker

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    Well, for this idea you'd have to try it yourself, or ask someone else at this point. I have no experience with this sort of thing, as I said it was a long shot in the dark idea.
     
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  12. BumbleBee

    BumbleBee

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    correct, HDMI can only transmit audio when video is also being transmitted.

    if your TV doesn't like HDMI from your receiver then the solution is to split the HDMI.

    http://www.monoprice.com/products/subdepartment.asp?c_id=101&cp_id=10110

    • run HDMI cable from computer to splitter
    • run HDMI cable from splitter to receiver to decode audio
    • run HDMI cable from splitter to TV then disable TV internal speakers
     
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  13. Kenshai

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    Most of those are one way splitters. Kind of a pricey way to do this.

    Going to have to say, I would use optical out from the TV to the receiver at this point. Easiest and cheapest way to do it. Wide range of cheap Toslink cables here.
     
  14. BumbleBee

    BumbleBee

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    what do you mean one way?
     
  15. Kenshai

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    One output, the cheaper dual output ones don't specify if they can do signals simultaneously. Also introducing a splitter can introduce increased latency.
     
  16. BumbleBee

    BumbleBee

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    the HDMI splitter needs to be active and HDCP compliant like this one.

    http://www.monoprice.com/products/p...=10113&cs_id=1011301&p_id=5418&seq=1&format=2

    these products are recommended all the time on Home Theater forums. read the customer reviews.

    Toslink can only transmit DD 5.1, DTS and PCM. HDMI can transmit DD 5.1, DTS, LPCM, PCM, TrueHD and DTS-MA.

    the option is there whether or not he wants to pay for it is up to him.
     
  17. Thatguy New Member

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    bad grounds
     
  18. BumbleBee

    BumbleBee

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    by the way Marantz, Panasonic, Oppo and Denon have Blu-ray players with Dual HDMI ports for the purpose of this topic.

    this is what Oppo has to say about it.

    one of the customer reviews for the HDMI splitter I posted above mentioned he connected a 75 foot HDMI cable to the splitter then connected another splitter to that without problems.
     
  19. twilyth Guest

    Yeah, I like the idea of using HDMI. I was aware of the limitations of optical and that's why when I got a decent audio system, I went with HDMI rather than optical. But this is for a tv basically. I don't really listen to music in that room. That's why I've been open to pretty much any alternative that would work at eliminating the hum.

    A splitter would actually be perfect as long as it doesn't interfer with using the HDTV as the second monitor. As I mentioned upstream, going from PC -> receiver -> tv would have been perfect except for the fact that the video card no longer recognized the tv when I did it this way.

    I have my other system set up like this with 2 samsung monitors. The monitor that is connected to the receiver works fine (a few glitches). So I think I must have a very old HDMI standard on the tv - it's about 6 years old.

    I'll try it again today to double check in case I only tried it with the original H67 graphics and not the new 5850.

    If that doesn't work, then I'll try a splitter and see if that causes the same problems.

    If it does, then I'll go with either the toslink cable from the tv to the receiver or i'll get the spdif bracket and go toslink to toslink.
     
  20. twilyth Guest

    I feel really stupid. It turns out that I never tried to connect via HDMI using the 5850 video card. I did that today and it works perfectly. I had tried using the H67 video on my motherboard and that definitely didn't work. But when I installed the new card, it didn't occur to me to try that out as well.

    I really appreciate the help everyone gave me in this thread and so that it doesn't go to waste, I'm going to try to consolidate everything I've learned, plus whatever else people thinks deserves mentioning, in a new thread dealing with digital audio generally - http://www.techpowerup.com/forums/showthread.php?p=2318021

    I don't really know shit from shinola, so if the new thread is going to be a resource for other members, I will need your contributions. :toast: :toast: :toast: :respect: :respect:
     

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