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A/V AKG K240 mkii - weird audio problem

Discussion in 'Hardware' started by David, 18 Aug 2020.

  1. David

    David μoʍ ɼouმ qᴉq λon ƨbԍuq ϝʁλᴉuმ ϝo ʁԍɑq ϝμᴉƨ

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    My youngest has a pair of AKG k240 MkII headphones, and he came to me and said the sound started to go funny. Sure enough, when I tried them, part of the audio sounds muffled/distorted like it's underwater.

    There's no obvious signs of damage to the headphones so I got another cable. Same problem.

    I sent that back and bought a different cable - problem persists.

    If I pull the plug out 2 to 3 mm it sounds fine, but it's literally sitting so loose in the jack that the weight of the cable alone can pull it free. The original cable is the same.

    I'm confused - any ideas?
     
  2. liratheal

    liratheal Sharing is Caring

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    I don't have those, but my thoughts are;

    - Dry solder joint somewhere in the headphones, probably around the jack area.

    - Buggered jack
     
  3. David

    David μoʍ ɼouმ qᴉq λon ƨbԍuq ϝʁλᴉuმ ϝo ʁԍɑq ϝμᴉƨ

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    Can't be a buggered jack - this happens on whatever 3.5mm jack I plug it into, regardless of what cable I use. Bear in mind it sound fine when I pull it out a couple of mm.

    That's why I'm confused
     
  4. Vault-Tec

    Vault-Tec Green Plastic Watering Can

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    OK.

    Are the headphones 4 prong? is the socket 4 prong?

    It will likely be a combination of the two if one is 3 pin.

    I have had that issue with modern headphones in the past, and sockets etc.
     
  5. Vault-Tec

    Vault-Tec Green Plastic Watering Can

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  6. David

    David μoʍ ɼouმ qᴉq λon ƨbԍuq ϝʁλᴉuმ ϝo ʁԍɑq ϝμᴉƨ

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    You mean four pole vs three pole 3.5mm jack plug?

    It's a three pole cable, but they've been working fine on the same PC since last August
     
    Last edited: 18 Aug 2020
  7. Vault-Tec

    Vault-Tec Green Plastic Watering Can

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    Hmm. Deoxit?
     
  8. liratheal

    liratheal Sharing is Caring

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    Oh, I meant buggered on the headphone side.
     
  9. David

    David μoʍ ɼouმ qᴉq λon ƨbԍuq ϝʁλᴉuმ ϝo ʁԍɑq ϝμᴉƨ

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    Deox what though?

    The cables are new - it happens on whichever device I plug them into and, if it was a problem at the headphone end (which is clean), why would backing out the 3.5mm jack a couple of mm fix the audio?

    See what I mean about confusing? It doesn't make sense.
     
  10. Vault-Tec

    Vault-Tec Green Plastic Watering Can

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    The socket? maybe it's got some oxidisation on the pins inside?
     
  11. liratheal

    liratheal Sharing is Caring

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    I'd be wrist deep in screwdrivers and teardown instructions at this point, but that's just the kind of weirdo I am.
     
  12. David

    David μoʍ ɼouმ qᴉq λon ƨbԍuq ϝʁλᴉuმ ϝo ʁԍɑq ϝμᴉƨ

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    I can see the three pin connector clearly - the pins and the contact plate are bright and clean. Again though, if that was the problem, how/why would this be affected/rectified by backing out the jack at the other end of the cable? I'm at a loss to grasp the possible causes of this.
     
  13. Vault-Tec

    Vault-Tec Green Plastic Watering Can

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    I have had this issue before. The pins on the male end pretty much can't be damaged ever. However, the pins inside can.

    There is one way I can think of to determine if the socket is damaged. You know how you said if you pull it out a bit etc? well do that and then run a proper stereo test (where it tests left and right speakers). If it is not running MONO through a short (which is usually what happens when you pull out like that (*sniggers* :D ) then it is highly likely the socket.

    If it still runs in stereo like that? it's probably still the socket. I have read through this three times and just so I am not being a total idiot have you tried the headphones on something else?
     
  14. David

    David μoʍ ɼouმ qᴉq λon ƨbԍuq ϝʁλᴉuმ ϝo ʁԍɑq ϝμᴉƨ

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    Like I said, the pins in the socket on the headphones are clean and straight - there is no obvious issue with that socket. the OTHER end of the cable (the 3.5mm audio plug) is the one I have to back out of the port a few mil to get decent audio. It is in stereo.

    I have been through three headphone cables and the problem persists. I have tried the headphones on my son's PC onboard audio, and with a USB sound card. I've also tried them on my PC, onboard and with a different USB soundcard.

    Nothing about this makes sense.

    I've been through the usual processes of eliminating possible causes - three cables and four different audio sources. I'd normally be pointing at the headphones as damaged/faulty but when I can get seemingly perfect audio by manipulating the opposite end of the cable, any cable, it throws doubt on why the headphones are the source of the fault.

    I was wondering if it was an impedance issue, but how that would manifest and why it would suddenly appear is beyond me.
     
    Last edited: 18 Aug 2020
  15. liratheal

    liratheal Sharing is Caring

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    Hum.

    I still suspect the jack on the headphones, sounds like something is misaligned/iffy if twiddling the other end 'fixes' the problem.
     
  16. Big Elf

    Big Elf Oh no! Not another f----ing elf!

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    Probably the socket based on my limited experience. I have exactly the same problem with the socket on the back of my TV. Like you I went through a few different cables, all with the same result.
     
  17. FILIPE MALISKA

    FILIPE MALISKA What's a Dremel?

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    Same headphone and same problem!so weird
    Did you solve the problem?
     

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