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.

145 thoughts on “Soldering The Thinnest Wires Ever Conceived: Headphone Modding

  1. Thank you so much for the post! I just rescued my own skullcandy earbuds that my rabbit bit through the cord of!

  2. Thnks…and its great and thats the same idea i used to have…but in case u dont have soldering instrument what wud u do? Ths is in rare condition only. I hav lighter/matchstick, swissor, needle and solitape…the thing is i can fixed it but it seems much more patient…and the work is ugly…well how wud u fixed in ths condition?

  3. Dude, great post but your wrong about the red/green twist .

    I was playing with the cables, with two headphones, one complete in my ears and the other playing the ipod peeled on the speakers end. When I touch the male jack of the complete headphone with just green and reed I dont get voice, But when I touch it with (red, green/red twist) and (green) the voice is added.

  4. Can give us a rundown of the tools needed to complete this job, including the vice thingy used to hold the wires? Thanks.

  5. I just did this! And when I did the second ear bud, I came to a better way to accomplish this ( or maybe just a faster method). Once you strip the headphone cable, just twist the cables together BEFORE lighting them to expose them, and then after they are twisted, light them up. It severely lowers the chances of wiring them up incorrectly, and eliminates the possibility of shortage. After twisting the ends I just folded each side to run parallel with the headphone cable, and then wrapped them up. It works perfectly.

  6. Thanks a ton for the post – extremely useful! Your technique of sliding the soldering iron along the wires worked well. For whatever reason, one of the ground wires coming from the jack did not seem to want to solder – that is, the solder simply would not stick to it at all. I don’t know if maybe I flamed it too long and changed the nature of the wire, or what – who knows…In any case, much appreciated!

  7. thanks! I saw the third green twisted wire and was like, WTF? F%$@ ME! What do I do now?… Ah!… Google! And I found you. Keep writing useful stuff please! Thanks again.

  8. Here is a old school way of dealing with an enamel coated wire. Its slick and works every time with any size of motor wire. It cleans the wire so that your solder will stick and you don’t have to worry about burning shit up with your mini torches. This may sound wild and weird but just give it a go and see if old school isn’t cool. It takes your soldering iron and an aspirin. Place the wire between the tip of your soldering iron and the aspirin. The acid (2-acetoxybenzoic acid) and the ingredients used to hold the tablet together in the aspirin will bind to the enamel and strip the wire clean. That’s it. You just have to have a real aspirin like Bayer because -Tylenol, Alleve, ibuprofen etc won’t work.

  9. Nice step by step DIY very helpful
    I also am doing the same but I added the sleeve from black 550 para cord on the outside by running the wires through the para cord before soldering all back together.

  10. I was desperate and hacked this completely. I didn’t solder at all, just stripped the wires, melted the acrylic off with a match, twisted them together, and held a match under them for awhile. After that I just covered them in a few layers of electric tape to try and hold them still. So far they’re working great. Thanks for the post, it helped me manage to do this! The tip about the acrylic coating was key.

  11. Alex, this a heartfelt thank you for this DIY soldering tutorial. I bought a Logitech powered spkr. system from Best Buy a ‘cable’ was cut (out-of-the-box ?). Inside that cable was 5 very thin insulated wires. I engaged in a clumsy attempt to connect those wires. Didn’t work. BB wouldn’t accept a return. Box set on the floor for five months…I’d read your instructions 5 months ago too. Not enough courage and skill to attempt the repair. Tonight …with your page in front of me and with a newly purchased soldering iron ‘n solder I finally sat down, and Pulled It Off!!! My lightweight system SOUNDS great! Thank you man! Thank you!

  12. do i need to solder the wires before it starts working? i burned the coating off and twisted the wires together but it doesnt work… i would really appreciate a reply.

  13. Hi Kai, sorry to delay. Theoretically, twisting the wires should be sufficient if you’ve gotten all the enamel off, but there certainly can be soot left over. I’d gently rub them down with a cotton cloth or something before twisting to see if that helps. In any event, soldering is definitely preferable.

  14. I am just reading this. I am up next. My NuForce earbuds have lost sound to one side-Hey, how do you locate where the break is? Anyway, I hope that I can get past the contemplation and fix the darn things. Thanks for the post!

    I have tried to solder/connect so many broken headphones before and I gave up on my really good headset until I saw this!!
    Thanks again 🙂

  16. I need to remove a switch from a set of PC headphones that have these coated wires. I can work with ‘normal’ wire well, but these things are giving me fits! Glad I came here. I see the burn off and aspirin/iron methods.
    So now, I’m good to go tomorrow. I really like these head phones, but that stupid switch for mode/volume is a PITA. It’s gotta go.

  17. Awesome guide you are a lifesaver. I made a quick and dirty method based on this, what you do is take the 2 wires and a wire of solder, twist all 3 together tightly, then burn it just long enough for the solder to start to melt, but not long enough to drip. Works 9 times out of 10, and only takes a min to do with no stress.

  18. Hopefully you will see this even though this post its old.
    i spend a lot of time repairing high end headphones such as bose, beats, etc.
    i used to solder the wires with this method you show in your blog
    but then i realized that the heat of the soldering gun has the perfect melt away that acrylic insulation just enough to be able to coat about a 16th of an inch of the tip of the tiny wire. no burning , no sanding. just put some solder on the tip of your iron and a little bit of flux on the wire. when you contact the solder with the wire the heat melts the insulation and solders the wire at the same time. you can finish any job ten times faster ( if you twist both of the wires together it solders both wires with a single action)

  19. message to hugo valverde. I have a pr of Etymotic-6i which I am prepared to pay to get fixed, right side fades in and out when I jiggle the wire. Let me know if interested in repairing, Thanks

  20. Alex, excellent post. I’ve repaired a ton of audio cables but never these tiny headphone things. I know a bunch of guys who would have a hissy fit if you told them to put the solder on the iron and pass the wire through it! I also have to say that mpower’s asprin post is great too! It also makes me realise I need glasses…ho hum…Many thanks from Northern Ireland!

  21. Hugo has the right idea. Using a match or torch provides too much heat and can ruin the copper. With a drop of solder on the iron you hold the wire in the drop and add a bit of resin core electronics solder and the wire will take the solder if a few moments. If you use flux it must be for electronics, any other will ruin the wire in a short time as most are acid. Does anyone know where you can buy bulk hedphone wire? The very fine enameled earbud type, 2 and 3 conductor type?

  22. I found that after burning the insulation off with a lighter, it helps to clean the wires with acetone. Otherwise the soot prevents the solder from sticking.

  23. Hey. I know it’s off topic but would anyone know where I can get a spool of headphone wire (similar to the apple headphone wire).

  24. I actually figured this out as a teenager (am 40 now) but always had mixed results. The torch is a great idea…

    The 1st time I figured out you had to actually burn the insulation off I was able to fix the headphones no problem… subsequent tries over the years resulted it either overheating the wires, accidentally breaking them off trying to twist them together, or the headphones just not working after what I thought was a successful repair…

    I think I might still have a broken pair of headphones lying about I might go back and take another stab at it. Now that I’m older, and financially much better off, I tend to fix things less if they’re too much of a hassle, since I can usually afford to replace things.

    Anyway, great post! I found this comment interesting as well “I found that after burning the insulation off with a lighter, it helps to clean the wires with acetone.” I’m wondering if that may have been the problem a couple of times.

  25. Thanks all. One thing that hasnr been mentioned is


    Even the oil from your fingers will coat the freshly acetoned wires and create problems with soldering.

    I dont understand but love the asprin trick….why that acid and not the acidcore solder?

  26. Thanks to this tip, I’m rocking out with my $200 Sennheisers again…

    The cable is separate (thankfully), but a new cable still costs about ~$40 and is hard to find because this series of headphones has been discontinued. After having isolated the break in my cable to near the headphone connector, I found aftermarket connectors by Acrolink for $12 shipped, and was able to snip the stock connectors off and replace them.

    I’ve listened to a variety of FLAC-encoded songs (classical, country, rock, metal, industrial, and electronic), and my fixed headphone cable sounds indistinguishable from stock. Saved me $25+, and allowed me to fix instead of throwing away (I hate throwing away anything when I know what the problem is and know I have the skills to fix it).

    Thanks again!


  27. Do you have any advice on not melting the plastic between the poles on a new tip/jack? Also, at the tip of a set of iphone earbuds, there are 5 twisted sets. Can you explain the mic/button part? Does the red/green just go to the second ring?

  28. Im trying to connect my Xbox 360 headset to the 4 pole iphone headset.
    Got the speaker working but cant figure out the microphone.
    Ive tried connecting the red/green twist to the Xbox 360 headset mic connector, and the inner white cable to ground but no luck.


  29. Fixed it
    If you unravel the red/green twist, inside is a white wire. The white wire is the microphone wire. The red/green strands can be connected to ground.

  30. While I don’t have Skull Candy earbuds, I am constantly amazed at the insane number of devices that use this absolutely worthless wire! I almost want to cut into the wire – before – I purchase anything that may use them! I have tried dozens of different techniques to repair them, but fail each time. I mean – ONE wire, no bigger than a human hair; how do manufacturers justify this garbage? Other than cost, of course… I’m about to try your method, which makes the most sense. (Why didn’t I think of that?)

  31. Excellent posting, civilized comments — apparently the trolls are afraid of solder … Actually I just wanted to drop some more old school on the people who have hissy fits about running a bead of solder over the wire to burn off the insulation. I used to design wire harnesses for these 30Kw satellite uplink transmitters, and all of the assemblers had a little crucible about half the size of a teacup at their stations called a solder pot. It was full of molten solder. When they were assembling wires into connector pins they’d (wait for it…) dip the end of the wire in the molten solder to burn off the acrylic insulation and tin the exposed copper wire in one step. These were military amps so the assemblers had to be trained to Martin-Marietta workmanship standards. They could only leave the wire in the solder for a very short time because soaking the wire would draw the temper of the copper and make it brittle. Same with using the tip of the iron as a miniature solder pot — time and temperature are critical. If the wire crumbles either the iron is too hot or you’re taking too much time to run the bead across the joint. If you don’t own a good Weller (or eq.) temperature-controlled iron, practice this particular technique a lot before doing it for keeps so you know how long I takes for your iron to overheat the copper. Good Luck!

    Zen Motormaster

    BTW — I like the aspirin trick — chemical stripping is the only alternative to thermal for this kind of insulation and the liquid stuff is expensive, hard to get in small quantities and dangerous to have around. Well done — Mr. Wizard would have been proud!

  32. Hi Alex,

    i’m a mechanical engineer, i was cleaning my drawer out and tossing junk.
    i came across these headphones and mic for a laptop/pc set. i had pulled the cables from the speakers and mic ages ago but kept the whole set with the thought of doing something to it. so now, i plan to put the set up in my helmet. but the wires from the speakers are broken off right at the solder/board. they’re circular shaped speakers with a arc shaped circuit board on one side with 4 terminals. and also there’s the mic with two wires coming out from it.
    could you please help me solder the whole thing up so that it works?
    so i have two speakers, a mic, the cable which ran from the headset to the plugs( and it also has the volume controls and mic mute options, i want to know if these work or if i can bypass them) and the mic and headphones plugs are separate. i want to change it to a single plug, use it with my phone.

    any and all help will be appreciated!



  33. Hi Alex,

    Thanks for the post! Helped me a lot. Also went with the tip Hugo gave: there is no need to burn of the insulation on the wires, the heat from the solder both burns of the insulation and also in one hit solders your wires together. In my case as soon as I saw the wires were covered in solder, the connection was good. The solder didn’t seem to stick if there was still insulation on the wires, so just keeping it there until it stuck was the way to go for me. Thanks again!

  34. you dont need that much hassle, put some solder paste on the end of insulated earphone wire(you definitely have to do this), get a drop of fresh solder on the tip of iron, put the end of insulated wire in that molten solder drop, then you will see the insulation melt and come out of that solder drop due to surface tension and solders adhesion to the copper.

    repeat it if youre joining two wires, and then join these two pre soldered points by soldering iron. or else just place the soldered tip of wire on a presoldered solder pad on a pcb, apply heat.

    results in perfect solders and joints %99 of the time. i’ve done 100+ headphones with this technique and before i struggled for another long period like most of you.

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