Soldering The Thinnest Wires Ever Conceived: Headphone Modding

Acrylic insulated wires stink, for sure, but when they're stranded and micro-fine, they stink WAY more.
Acrylic insulated wires stink, for sure, but when they’re stranded and micro-fine, they stink WAY more.

I may use this blog to post mainly iPhone or software related articles, but I am an electrical engineering student, and as an EE, I love me some good, clean hardware. Therefore, when my favorite pair of earbuds kicked the bucket the other day, my first thought went to the in-box iPhone headset and, more importantly, how much those earbuds suck. My favorite bang-for-the-buck earbuds EVER are Skullcandy Full Metal Jackets, primarily because I got them at TJ Maxx for $25. In general though, they have silicone pads that seal out sound, instead of the hyper uncomfortable iPod earbuds that fall out and sound like crap. I was super bummed when my FMJs broke, but luckily, the part that broke was on the plug end of the earphones. That is, both earbuds themselves still work fine, only the plug is dead. My thought was to cut the crappy iPhone buds off their cable (which includes a microphone and remote button) and graft on my beloved FMJs.

The only thing stopping me? These heinous, hellish stranded acrylic-insulated wires:

The traditional method for dealing with single stranded acrylic insulation is sand paper – you just sand the plastic sheathing off the conductor. The problem HERE is that, clearly, these are NOT single stranded. Trying to sand them with even the finest sandpaper results in a frayed mess that looks like a frayed cotton thread. Without getting the insulation off, though, you can’t solder the wires together or otherwise make any connection. Another method is to try to melt the acrylic off with the soldering iron itself, but this can get messy plastic on the iron and, more importantly, the prolonged heat exposure has a tendancy to melt the jacket farther up the wire.

Notice my friend, the pencil torch, on the right. IDEA!
The torch makes quick work of the insulation. Check out the secondary flame though: that’s the insulation burning off BEYOND the spot directly in the torch flame.
Prepping the joing for solder.

My favorite method: The melting technique got me thinking, though, and being a pyro, it wasn’t long before I saw the pencil torch sitting on my bench and had a brainstorm. As it turns out, burning the acrylic off outright works quite well, and with the extreme heat of the torch, the wire heats up so quickly that it doesn’t have enough time to conduct much of that heat to the jacket above. The result is a fairly clean removal of the insulation, at least plenty to make a nice solder joint. The real trick is to move FAST! Only burn the very end, because that will usually be enough to catch the acrylic on fire for a few more milimeters up the wire, and as SOON as you see the wire start to glow, remove the heat, because that’s how you know there’s no more insulation over that portion (it’s already burned off) and if you let it sit there, the wire will melt almost instantly leaving you with none to work with.

The prepared wire. It's difficult to see, but if you look closely, you can make out the slightly different metalic look near the end. That's lightly-soot-covered but uninsulated wire. Solder, with a little coaxing, will stick to this.
The prepared wire. It’s difficult to see, but if you look closely, you can make out the slightly different metalic look near the end. That’s lightly-soot-covered but uninsulated wire. Solder, with a little coaxing, will stick to this.

Now the trick is to actually solder the wires. You’ve got them stripped and ready, but they’re still super fragile. I used two sets of tweezers to wind the two ends around each other. Really all this requires is a whole lot of patience.

Shrink tube shrunk. The piece of blue on the left is to go over everything, and then there’s another red one behind it to go over again.

After the joint is fixed enough to not fall apart during soldering, you can go ahead and start soldering. The wires are so small that the solder doesn’t really stick, so what you have to do is, as quickly as possible, melt the solder onto the iron, but with the joint DIRECTLY in the middle of the two. If you do it right, you get a big melted bead ON the iron, but with the wires running through the middle of it. Drag this up and down the wires, and that will be enough to solder them together. Try not to leave extra – it’s brittle and these wires can’t really flex. Also, DON’T FORGET TO PUT YOUR HEAT SHRINK TUBING ON FIRST. I CAN’T STRESS THIS ENOUGH, I ALWAYS FORGET. I used multiple pieces, two very small ones on the individual conductors, then at least two over the whole system for strength.

Another helpful tip is to use the torch to shrink the tubing too. You don’t want the tube in the flame, that will catch it on fire. You also don’t want to leave the torch pointed at it long, that will to. The trick is to wave the flame so that the plume of hot air above it licks the tubing. When this happens, you’ll see the tube shrink fast. Keep going back and forth until you don’t get any more shrinking. It takes some getting used to, so maybe practice before you torch your headphone cable.

The finished product is a thing of beauty. Ok, maybe not, but that’s mostly because I ran out of white heat shrink tubing. Oh well.

The guts. The cannibalized Skullcandy cord and the crappy iPhone earbuds in their proper place: cut apart.
The glory. This is the completed product, gory red shrinktube and all. On the plus side, my FMJs now work again, and with a microphone and remote play/pause/answer/hangup button to boot!
The glory. This is the completed product, gory red shrinktube and all. On the plus side, my FMJs now work again, and with a microphone and remote play/pause/answer/hangup button to boot!

But wait! If you acually tried to do this yourself at home, you probably noticed something peculiar about the iPhone headphones. Namely, what the DEUCE is that red/green twist?

What is that red/green twist and what is it doing in my right earbud?!
What is that red/green twist and what is it doing in my right earbud?!

As it turns out, it’s the microphone cable. That makes sense – there are two copper-colored ground wires, one for each bud, there’s a red wire for the right bud, and there’s a green wire for the left one. That leaves at least one wire for the microphone, so one of the red/green twist is probably also a ground, and one is for the mic. My guess is that the button in the headset shorts the mic return line to ground, and the iPhone hardware looks for that, but it’s mostly inconsequential. Maybe I’ll play with it at some point, but for now we’ve got everything we need.

The real question at this point is, what is that twist doing going all the way up to the right earphone? Short answer? Nothing. The twist just dead ends in the headphone, the only connected wires are the red and ground. So you can just ignore them. I’m not sure why Apple chose to continue them past the mic, but whatever. Cut them off so they don’t short against your solder connections, and that’s all you need to worry about. It turns out thy’re used as an FM antenna for iDevices with integrated radios. Don’t worry about them unless you have an iPod Nano (and you actually use the radio).

So now you can solder ultra fine wires, and maybe you even got a nice new headset out of the process. Finally, I’d like to thank forum user Zerologic for this (coral) forum post, which is where I got the info on which wire was which. Sadly, I can’t properly link to his site since the forum requires you to log in to see profile information.


  1. Eric
    April 11, 2010

    I’ve only had success soldering headphone wires once. They came from a cheap pair of sony headphones(probably came with a cd player or walkman). Instead of the wires from hell, each wire was a twisted set of magnet wire strands. They soldered extremely well. I wish all headphones were made this way. I’ll try the asprin trick next time. Thanks for the tips.

  2. Al
    April 14, 2010

    i always flux the strand and use an iron at about 350dC
    they solder relatively quickly with minimal heat spreading
    the biggest issue i have with burning the enamel off is that it embrittles the wire.
    but yeah, scraping or sanding is comically futile

  3. Ermita
    April 27, 2010

    Thanks a lot buddy. You just saved me £15 of new cable for my Sennheiser HD 575. Really helpful tips and picture. Problem with mine was the 3.5mm jack not the cable so cut this off and manage to find an old not working mobile phone headphone. And uses the jack off this. Works a treat again. I’m not electronic guy that solder stuff but due to the very good explanation and picture manage to make my headphone works again.

    Funnily enough did forget to put the heatshrink cover first and realize this after the first solder. But worst was after I done everything and tried the new cable. There was no sound WHAT! So I cut the cable again but only to realized that the other end is not connected to the headphone at all. DOH……lol….All good now. Thanks.

  4. Mondo
    May 5, 2010

    Great tutorial man, it helped me a lot, thanks.

    Now a thing about that mysterious red-green wire (though probably someone has mentioned that before me) – I was practicing with a pair of earphones from iPod mini and it was there, along with the green wire, inside the cable for the left earphone. No way there’s a mic in iPod mini’s earphones. So I guess it might be a variation of the copper wire in the right.

  5. Kyle
    May 6, 2010

    thanks, fantastic advice. just burned the insulation and varnish off with a lighter.

  6. Sandeep
    May 30, 2010

    Hey there,

    I googled quite a bit to come to this page, ok, similarities, I too am an EE and i too got a FMJ (or is it ink’d) and the kick of its bass is what’s keeping me going with this product. Unfortunately i too had a problem with its Jack and had it cut, tried different soldering techniques to get it fixed. But I am not able to get the old punch back. Here’s what I did:

    Once I cut the wire, the white outer has the following inside
    a. a covering of golden copper wire
    b. a red copper wire with insulation and
    c. a blue copper wire with insulation.

    So first I bunched the golden copper wire into a bunch. and has the blue and red separated.

    I bought a new Jack instead of using old Apple’s Jack (I still have them though), This new Jack I got has three pins a small contact (+), a big contact (-) and a much bigger ground.

    On my first attempt i connected the blue to +, red to – and the golden copper to ground. Unfortunately, there was no sound at all, possible because of the insulation not sure. So started experimenting.

    Second attempt, to the first blue and + connection i attached a lil bit of the golden copper from behind and so also to the red and – connection. There was sound but the solder did notmake a good contact, kept coming off.

    Final attempt, connected the same contacts as above but, the golden copper connection was attached in such a way that there was no solder used and the main wire holding handle was used to grip the copper. It sounds good but not as good as the good ol’ days. Where am I going wrong. I have an ipod touch and simply cant buy a new FMJ cos I am now in India and they dont sell that here, I bought this when i was on a trip to the USA. please help

    Was wondering what kind of connection made this thing work, is it designed that way, or was my trial and error actually getting lucky. Please help, I have spent my entire weekend on this. Much appreciated, thanks.

    Anyways I am trying to heat off the nylon insulation on my red and blue wires today, let you know if the performance improved. Mail me on my e-mail address


  7. Johnny
    June 18, 2010

    Fantastic tutorials. Save my day as I was struggling how to repair my Sony earphone and I did it following your advise. Thanks mate.

  8. Ben
    June 18, 2010

    What size heat shrink did you use for this?

  9. Harold
    July 11, 2010

    If you don’t have heat-shrink tubing, you can use hot glue (those pencil-size sticks of glue that stick into a warming gun)–it insulates well. If you do use it, go a little way up the outer insulation to make the whole splice stronger. It is stiff, but only maybe 1 or 1.5″ long.

    I do this for something different: I shorten the cable on my mp3 player earphones for sports so that I reaches down to my waistband with a minimum amount of slack. I also put both the red and blue wires together to go to one earphone, since I like to have one ear free to hear traffic or the world around me. I listen mostly to podcasts, so sound quality isn’t paramount for me.

    Great page of advice, thanks!

  10. TempE
    August 5, 2010

    If $25 FMJ Skullcandy’s are the best bang for the buck you’ve ever heard then you’ll be frickin’ blown away by Meelectronics’ M9 and M6. Give ’em a try, they’re amazing.

  11. R Moribayashi
    August 18, 2010

    If you don’t want a bulge in the wire and you have a little patience you can order plugs on the internet for a few bucks. I always try to keep a few handy just in case. Search for 3.5mm (or 2.5mm for the smaller ones) and TRS if the plug has two plastic rings or TRRS if it has three. You will have to do some research to find the wiring for your headphones, especially for TRRS headsets or figure it out with a working pair and a meter. By the way, the initials come from the parts of the original 1/4 phone plug used in telephone switchboards over 100 years ago, the tip, the ring and the sleeve.

  12. tim zenner
    August 31, 2010

    Very nice article man, I found this after trying to repair my old headphones and finding out about this evil acrylic insulated things. A pencil torch like yours would have done the trick, what model do you use/recommend? I must have one 😀

  13. YourFriendBen
    October 4, 2010

    Never though to torch the acrylic insulated wires. Don’t know why. Thanks for sharing.

  14. j-lovin'
    December 3, 2010

    i love you. you saved my headphones from treachery.

  15. December 16, 2010

    Damn those ARE some thin wires…Can’t have too much caffeine when doing that.

  16. David
    December 19, 2010

    Thanks dude! It’s the first time I solved my mic problem! They just stopped working today! So I took some trash pieces I had and built a new mic and it’s perfect based on your article! keep the good work!

  17. futureboy
    January 3, 2011

    One suggestion for pre-solder prep:
    The beading of the solder is usually caused by oxidation. Most metals oxidize, especially when heated. Solder with oxidized metals is like oil in water, so try using a little flux on the wires before soldering, as a joint with oxidized connections is very brittle and often unstable. If you don’t have any flux, then you can try cleaning the oxidization off any other way. Scrubbing with a scouring pad wet with vinegar might work. Rubbing alcohol should work also. Then your solder with flow with ease, also removing the dangers of a brittle joint.
    Also, always remember to keep your solder tips tinned!

  18. Steven
    January 15, 2011

    I could use some help with a slightly different need and hope you can assist. I have a cordless phone headset, gaming headphones, and Zune ear buds that all need to have the connectors replaced because of pulling. I cut the jacks off and bought new connectors but can’t figure out which wire goes where, how to prep the wire and how to solder to a jack instead of wire-to-wire.

    Ear buds are one cord with red/green/copper which I assume are right/left/ground.
    Headset cord is a pair red/copper & white/copper. Red through one hole, white to the other and both grounds to center?
    Gaming headphones cord is a pair: one with red/green/blue and the other is a single black.

    The main problem is that the red/green/blue wires don’t seem to be wires as such. I tried stripping and burning the insulation away to expose the wire, but there was no wire as you show in your photos. With a magnifying glass I was able to see literally only two tiny copper wire strands that would be impossible to separate and solder. It looks like the whole thing (unstripped) would have to be soldered on.

    Which is the other question. Who exactly do you solder wires like these onto jacks?

  19. Derek Lewis
    January 16, 2011

    Thanks for the tip about burning the insulation off. I was adapting a pair of iPhone headphones, with mic and button, into my ski helmet, and wasn’t sure how to solder the insulated wires. I didn’t have a pencil torch, but a plain old lighter did the job fine.

  20. Brad
    February 28, 2011

    a) Thanks for the detailed explanation. Well done. I never would have realized that the wire is hidden inside that thin acrylic layer.
    b) Similar to Derek’s comment – I had to ad lib with a plain cigarette lighter and duct tape, since I don’t have the equipment you described. Works fine, so far..

  21. April 13, 2011

    Dude, this was great. I’ve been trying forever to fix my mom’s headphones with major hit and miss progress. Then I was reading your blog and it said something about an extra coating on the wires that you have to burn off. Brilliant. Turns out that holding the soldering iron on for an extra ten seconds melts it enough for the solder to stick a little.

    Great posting, nicely documented and very thorough. Thanks again.

  22. bob
    May 18, 2011

    if you think thats small, try soldering together the wires in a broken headphone driver

  23. Kim
    May 29, 2011

    Man I was just thinking abt doing the same thing! Funny thing though i used a cheap cigarette Lighter to do this n it was freakingly easy! I Just twisted the needed coated wires n burnt them 🙂 n my philips Headset is back!

  24. Alex
    June 3, 2011

    Great how-to. Just fixed up my broken Sony in-ears, saves me $40 for a new set. Matchstick, twisted the wires and a dodgy solderjob. The tape looks ugly as sin, but it works. Thanks a tonne!

  25. DButler
    June 9, 2011

    i have always found it cleaner to go right into the headphones when swapping the buds to different wires (any other headphones onto the apple with mic/remote) generally with a sharp exacto knife they pop apart pretty simple (look for joints where colours change, and for apple they hide it on the inner of the grey rubber pad), from there you can string the wires through, solder them to the speakers, and then just re-seal it up with superglue or hot glue or similar. i have fallen in love with the ipod’s remote and can hardly live without it anymore.

    also for the headphones with a mic/remote (have 4 sections r/l/g/mic) after much searching i found a diy plug here ( and I’m looking for a place to get the soft strung wires they use for headphones so i can custom wire my own i have spent too much on headphones have have easily half a dozen or so sets that work perfectly only need the wires.

    ALSO it’s an easy way to get free ear buds (buy a pair, return it missing one bud, and do that a few times alternating buds.)

    would love to use similar wires guitars use (big and heavy) but for earbuds the wire is far too beefy, if you get a nice pair of over ears that are big enough i highly suggest it would last much longer.

  26. Zachary
    June 12, 2011

    Everyone does realize Skullcandy’s headphones are lifetime guaranteed? In other words they will send you a brand new pair if you send them the old pair!! Just thought I’d letcha know!

  27. Alex
    June 23, 2011

    Oh shit now you tell me. I threw out my broken skullcandys a few months back…I liked those ‘phones!

  28. Giles
    August 5, 2011

    You rock! Saved me my favourite pair of earbuds that got ripped up in my bike. Works perfectly!

  29. Yi
    August 12, 2011

    For those that don’t have a torch.

    Heat up your stove element to high, until it’s red hot, press each wire against the coils for about half a second. The acrylic will be completely gone. Next unroll each wire to separate the copper from the (string?) lining. You now have wires ready to twist.

    Worked great.

  30. Edward Anderson
    September 5, 2011

    Thank you! I was struggling with these iPhone ear buds the other day, trying to use sandpaper. I appreciate your advice! Also, like DButler, I take apart the earbuds and re-solder everything inside there. MUCH cleaner.

  31. John Burel
    October 2, 2011

    I must say that you have made a very good post and would love to add a suggestion. What I have been doing for all of my acrylic wire soldering projects. But first let me say not to knock on the flame idea because it is the very idea I used before this one. I found the wires tend to get brittle and charred and because the wire is so small the heat distribution makes the fall off so abrupt the usable area is also brittle so for maximum strength I came up with this.

    1. I tin the tip of my soldering iron and form a small puddle (1-2 mm ball) of solder on the tip

    2. Then as I am holding the wire (BEFORE ANYTHING IS ATTACHED) I take it and rest it in the puddle until you see the acrylic boil to the edge of the solder

    3. Now because I form the puddle of solder the acrylic waste does not stick to the soldering iron and you just have to tap the excess into a ashtray or bowl or your soldering station waste tray

    What you accomplish by doing this is you tin the wire wherever you are connecting it to make for faster soldering once your working with your component to keep down on heat damage for the wire and component (as we all know brittle wires and burned up plastic sucks when your working on those “one shot” projects). you also benefit from have the acrylic coating all the way up-to your solder joint.

    Things I have repaired:

    Xbox 360’s
    Turtle beach Gaming Headsets
    Touchscreen car dvd players
    Car stereos
    LED TV’S
    Projection TV’s
    Desktop Computers
    Standard Earphones
    Police Lighting Equipment
    Surveillance camera Equipment

  32. B Arch
    October 11, 2011

    Quick question, even though the mic wire extends clear up to the headphone, will this effect the mic in any way? It will all still work even when it isn’t taken clear up to the headphone anymore correct?

  33. henry richmond
    November 8, 2011

    thank you very much for a really usefull tip.
    Very well done with clear photos,
    and infrormative text

  34. Zeke
    November 9, 2011

    I have a question, I did this and got sound to come out of the headphones. The problem is the remote does not work at all. Any ideas?

  35. November 9, 2011

    Zeke, I’d be willing to bet that you accidentally soldered the microphone wire to one of the other two on that side. The mic wire (a twisted red/green pair, also used for remote functions) extends past the remote for some reason. It should be ignored, but this exact situation could arise if you accidentally soldered that to the ground lead of the headphones (or, I suppose, to the positive lead).

  36. Darrel Walters
    December 1, 2011

    Hi guys
    can I ask does anyone know where I can get the wire for making new cables sets, hunting hi and low and yet to find a side
    Helps Please

  37. December 5, 2011

    thanks, been trying to fix mah sony mdr-v6’s for ever, kept eff’ing up… this should do the trick!

  38. Nam
    December 13, 2011

    Thanks man just what i needed.

  39. Bam Kaboom
    January 17, 2012

    the same as henry richmond said!

  40. January 22, 2012

    Thanks for the great How To, Alex. You helped me save my $100.00 bike helmet headlight. The roads are lit once again!

  41. k_fred
    February 10, 2012

    the red and green wires going up the earbuds are used for antennas for radio functions in other ipods. its neat how it works but if you don’t have a ipod nano then they are useless to worry about

  42. February 12, 2012

    […] and ultra small wirestrands that are used today, soldering can be a challenge – check out He’s not exaggerating. I came across some nonfunctional but comfy headphones the other day. […]

  43. Allen
    April 5, 2012

    I figured out how to melt insulation too, my daughters cat munched the wires on my favorite earbuds. I simply used a bic lighter to get wire glow. Make sure you use high quality 40/60 electronics solder if not you’ll be sorry.

  44. d-dot
    April 5, 2012

    worked great

  45. Charlie
    April 18, 2012

    I have a set of bose earbud that the wire (White/Black) insulation is disintegrating. I would like to replace the whole wire with replacement IEM cable with a standard 2 pin connection. I would like to cut off the wire from my buds and connect a female 2 pin connector so the replacement wire would just plug in. I’m not sure were to purchase the female connector. I think heat-shrink tubing could provide support for the cable/female2 pin connection. Any advice or information is welcomed…

  46. David KIII
    April 25, 2012

    You can also use your soldering gun to heat and contract the shrink tube. Run it along the shrink tube, yes, you can touch it and it wont melt. This method is good when you cant use fire and/or tight spots.

  47. Darin R
    May 13, 2012

    Thanks for posting this… I had the horribly designed plug on my Klipsch S4i earbuds, which sound AMAZING but have a horrible design flaw with the connector, go bad and I really didn’t want to drop another $100 for another pair. Got ’em all fixed up thanks to you. 🙂

  48. May 23, 2012

    Different headphones but… Is the small black wire here the one in question? If so, what is with the copper “hair” that surrounds it?

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