Reterminating Headphones to Balanced

Discussion in 'DIY' started by Luckbad, Jan 16, 2016.

  1. Luckbad

    Luckbad Traded in a unicorn for a Corolla

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    Any rules of thumb or guides for terminating headphone cables to 4-pin XLR?

    I can do basic soldering. I need to convert my JVC HA-DX2000 to balanced and make a 1/4" adapter out of the single-ended terminus.

    Thanks!

    Update: I've seen questions about converting Sennheiser HD650 cables to balanced. This info is on the link @Xen provided.

    https://robrobinette.com/BalancedCable.htm#Sennheiser_HD
     
    Last edited: Aug 5, 2017
  2. Xen

    Xen Friend

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  3. Luckbad

    Luckbad Traded in a unicorn for a Corolla

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    Yep, that is what I want to do with it.
     
  4. PoochZag

    PoochZag The Shadow knows - Friend

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    While I make my own cables, the main thing that's caused me pause to try a termination of a fixed cable (thx00 soon) is this...

    I cut off the plug, how do I know which wire is which? (assuming they're not all uniquely colored so looking where they're soldered on the plug won't help).

    I get I can use continuity to determine pairs, but which pair is left, and which is positive... Etc?
     
    Last edited: Jan 16, 2016
  5. SoupRKnowva

    SoupRKnowva Official SBAF South Korean Ambassador

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    This is something I've wondered as well with a fixed cable like that. But I guess if you weren't going to reuse the existing plug, you could disassemble that plug and look at which wires are soldered where to the 1/4" plug...but I think with most OEM cables you wouldn't be able to reuse it after doing that? So it would be for science :p
     
  6. Xen

    Xen Friend

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    Telling which pair goes into the headphones will be easy - they will make a circuit.

    Telling which one is + or - ... that will be harder. I have never done a re-termination with non-detachable wires before, but here is how I would approach it, by my preference.
    1. Take apart the cups and see how the drivers are wired. - Hopefully the least destructive method unless cups are glued.
    2. Take apart the TRS and see how it is wired, then rebuiild the TRS. - At worst, you buy a new TRS plug.
    3. Take apart the connection at the cups. - Last resort as you will have bare wire you will have to repair with electrical tape/epoxy/hot glue/etc.
    You hope that they are multicolored. If not, you will have to find an exposed bit of wire or worse, make a bit of wire exposed. I would expect the drivers should have exposed metal for testing continuity.
     
  7. Luckbad

    Luckbad Traded in a unicorn for a Corolla

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  8. fraggler

    fraggler A Happy & Busy Life

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    If the THX00 cable is anything like other Fostex/Denon cables (99% sure they should be), then the wires will be differently colored so figuring out R+, L+ and the two Gs should be easy enough. Figuring out which G goes where is a little more complicated since they are likely to be the same color and spiraled up through the cable. I haven't tried testing for a circuit before since most of the time when I have dug into a headphone with attached cables, it has been to replace the cable. If it works, then it should get you closer once you decipher the colors. If you look at this page, you will see the various cables taken from the Denon/Fostex line: http://www.lawtonaudio.com/saleitems.html Traditionally, I would think that red would indicate the right channel, with the alternate color being the left channel. Which ever wires are the same color should be ground. You can always wire it up one way, use your adapter back to 1/4" and do a Left-Right balance test. If Left is left, and Right is Right, then game on! If not, just swap them on your XLR and then, game on!

    Personally, I'd just dismantle the headphones, desolder the wires, do a quick continuity test, then resolder the wires and move on. But if this is your first time doing this, maybe don't, since if you leave heat on the solder pads on the driver for too long, you will likely kill it.
     
  9. fraggler

    fraggler A Happy & Busy Life

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    Nice find. You should be good with that. Like I posted before, if you get L and R mixed up, it is as simple as swapping them. You won't damage the headphones.
     
  10. PoochZag

    PoochZag The Shadow knows - Friend

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    Thanks for the Fostex info. So, I chop off the plug, look at the 1/4" plug, and then know what R+ and L+ are because of where they're soldered on the plug. Then couldn't I then figure out R- and L- by checking continuity as they'll make a circuit with the driver? Or is it not that simple?
     
    Last edited: Jan 17, 2016
  11. Xen

    Xen Friend

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    That is what I would try first.
     
  12. JK47

    JK47 Guest

    I reterminated my TH-x00 to 4 pin XLR, I'll post a pic tonight after work of the wiring.
     
  13. JK47

    JK47 Guest

    The close up pics I took suck, but I went with:

    pin 1 L+ = Blue
    pin 2 L- = Brown
    pin 3 R+ = Pink
    pin 4 R- = other Brown

    Open one cup and check for continuity to find the brown wire that belongs to that side's - . I marked it with a felt marker and soldered away. Also used a piece of electrical tape (could also use heat shrink) to stop the woven sheath from unraveling.
     

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    Last edited by a moderator: May 23, 2016
  14. johnjen

    johnjen Doesn’t want to be here but keeps posting anyways

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    Another strategy is to cut the TRS plug off ≈ 1-2' from the end.
    Use this to make up an adapter to go back to unbalanced, if so desired.

    Then look at the wires on the cut end that lead to the HP's
    Usually they are color coded.
    One pair of wires will connect to a driver, which leaves the other pair of wires for the other driver.
    A dvm will provide this info.

    Again usually they are color coded with the 'bright' or primary color(s) being + and the darker or secondary colored wires being —
    There are however cases where these bright vs. dark color schemes are reversed.

    In the end it matters not IF you have access to DSP where you can invert the phase of either or both channels and compensate for any mis-wiring.
    And once any mis-wiring is identified then just re-solder the wires correctly.

    AND/OR,
    you can also use the TRS cable to help identify the + from the — colors, and which color is left and which is right.
    The tip is left and the ring is right.
    And the 2 — wires are a dead short together, where as the + wires aren't.

    These tests will provide a 'map' of the colors and polarities of the wires.

    So if you add a female 4 pin xlr to the TRS pigtail adapter, and a male 4 pin xlr to the cable that runs to the HP's you have a means to connect up to any 4 pin balanced or unbalanced amp.

    And as an added bonus you can also add a phase reversal cable to the end of the 4 pin male and explore that tweak as well.

    JJ
     
  15. JewBear

    JewBear Almost "Made"

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    When you check continuity put the headphones on your head. You'll hear a muffled pop in one or the other ear.
     
  16. philipmorgan

    philipmorgan Member of the month

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    I just did this rewiring job and wanted to note for others that the wire pairs for each channel are twisted together, so it's possible to locate the ground for L and R by noticing which color wire it's twisted together with. On my Purplehearts, the ground for the right channel was the brown wire that was twisted together with the pink wire.

    I did a continuity check just to be sure anyway :)
     
  17. gaspasser

    gaspasser Flatulence Maestro

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    Thanks to @philipmorgan and @JK47 I just was able to easily accomplish the TH-X00 retermination on my Mahogony pair to 4 pin XLR. The process was straightforward and good soldering practice for a newbie like me. Man, what a difference on Jotunheim! The soundstage and upper registers sound much, much more open.

    Edit:
    I also successfully reterminated the cut SE end into a 4-pin XLR adapter!

    This thread and you gentlemen made this happen. On to cable making!

    Also thanks again to @powermatic for the soldering station! image.jpg
     
    Last edited: Mar 24, 2017
  18. Pars

    Pars New

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    Kind of mentioned in a couple of post, but with a DVM set to ohms (on lowest range if not autoranging, or on a high enough range for the phone's impedance), you can determine this easily if the wires are color coded, without disassembling the headphones:
    1. Leave enough cable on the cut off plug to strip the wires. Ohm out tip of the connector to the stripped wires. The wire it connects to is L+; note color. Ohm out the ring of the plug; the wire this connects to is R+.
    2. Ohm out the wires going to the phones. Most phones won't mind this, but I'm not sure if this will not damage any headphone out there. Ohm out the L+ to the two GND candidates. The one that shows a resistance will be the proper wire for L-. Check R+ and the other GND candidate to see if it is a similar resistance. This will be the R- wire.
    Good advice above as well on leaving the cut wire long enough to use the plug for a Bal->SE adapter with the proper XLR connector(s).
     
  19. gepardcv

    gepardcv Almost "Made"

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    Does anyone have experience running the Oppo PM-3 balanced? Its headphone side cable connection is a 3.5mm socket, and the two cables it comes with terminate with TRS jacks. I haven't tried to disassemble it, so does anyone know if the headphone side can accept a 3.5mm TRRS jack, and if so, which wire corresponds to L+, L-, R+, R-? I saw a couple of aftermarket balanced cables, but am not sure they are truly balanced, or if they just have 4-pin XLR jacks and silently ignore the negative sides of both channels.
     
  20. PoochZag

    PoochZag The Shadow knows - Friend

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    It's wired for balanced, I made a few cables for it when I had it. The stock cables are just TRS because that's all you really need if the termination is also single ended. The graphic linked below is really nice as it has the pinout for the PM3 socket, as well as a couple typical amp side balanced jacks.
    https://cdn.head-fi.org/a/7402425.png

    If you're specifically looking for Oppo PM3 balanced to 2.5mm TRRS balanced I may have a cable laying around, I don't have the PM3 anymore
     

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