Thursday, April 10, 2014

Sony MH1 Re-cable Tutorial

UPDATE: Newer re-cable tutorial is being developed that includes soldering straight to the drivers! (more stable and professional looking). Please look for the new post once it posts soon.

I promised some people over at an audio forum that I'd make a tutorial on how to re-cable the Sony MH1 earphones.  Sorry for the long wait, but here we go...

(Note: This is an incomplete article. See below.)

Before explaining the process, some people might be thinking, why would you want to re-cable an earphone?  There are a number of reasons, and the MH1 seems to have them all.  It is one amazing earphone connected to one horrible cable.  First, they are designed to be worn behind the neck.  This allows you to have the microphone close to your voice and gives you the ability to remove them from your ears and let them rest on your chest (nice during a workout).

However, even still, the flat design of the cable make them a little unwieldily.  It also makes them very difficult to wear over the ear if you wanted to.  This is important, because they transmit cable vibrations into noise in your ears very very easily.  Wearing them over the ears almost completely eliminates this.  The included shirt clip helps noise, but doesn't eliminate it.  I find wearing them in front of you with the cables run around the ears is doable if you're careful, but not ideal.

Finally, the cable is a royal pain to wrap for storage.  The uneven y-sply of the cable along with the remote controls and mic section make it hard to simply wrap up and put in a smaller case.  So, what are we to do?  Re-cable them of course!

The following tutorial will replace the cable all the way up to the strain relief of the housings of the earphones.  I've seen people replace the cable right into the housing itself, but that would require more effort and more likelihood of damage.  However, it also might be that the connections last longer.  I'm not sure.  I'll update this tutorial if I end up trying that method.  Otherwise, onward we go.

This tutorial will assume you have some basic knowledge of elementary electronics and how to use a soldering iron and multimeter.  I will still describe how to use these tools for this tutorial, but that is not a replacement for proper training or safety.  I cannot be held responsible for any damage to your earphones or yourself by the use of this tutorial or if you burn your house down.  Proceed with that knowledge. :-P

First, here is the list of items and tools you will need:
  • Pair of Sony MH1 Earphones
  • Soldering Iron or Station (preferably high quality temperature controlled)
  • Solder (preferably Kester 245 or similar 63/37 or so mix)
  • Digital Multimeter (analog is o.k. too)
  • Butane Lighter (other lighters may work)
  • Sharp knife/Exacto/Razor
  • Electrical Tape
  • Heatshrink Tubing
  • Roll of 24-28 gauge wire (I used 24 awg)
  • Small Gauge Wire Stripper
  • Neutrik 3.5mm Right-Angle Plug (NTP3RC or other preferred plug)
Some tools and an alternative straight plug (Neutrik NYS231)

$7 roll of 24awg speaker wire from local hardware store

Neutrik NTP3RC (exploded view)

Hakko FX888D Soldering Iron (very nice, temperature controlled)

Cheap digital multimeter (works great!)

I found the necessary items for this project at the following prices:
  • $20.00  Sony MH1 Earphones (
  • $3.50  Neutrik 3.5 plug
  • $7.00  50' roll of 24 AWG speaker wire
  • $3.00  Pack of assorted heatshrink tubing

  • Total:  $33.50
  • Cost to re-cable: $13.50
The first thing you should do it practice the process.  To do this, I cut the cable of the MH1 well below the area where I ultimately would make the final cut.  This way, I was able to slice and cut, solder and test, all without risking ruining the whole process by making a mistake with only .5 inches of cable to work with.  You can simply follow the basics of stripping and soldering the wires in this tutorial with the portion of the cable you cut off until you feel confident in making the final modifications.

I opted to make the entire cable first and then join that to the small cable I left coming out of the strain relief of the housing.  To make the initial cable, you need to unroll a length of wire that is roughly five times the length of cable you plan on having for your earphones.  This is because, depending on how you braid the cable, you will need four total wires connecting the parts of the earphones (two per driver = four) and the rest accounts for the loss from braiding (very minimal), stripping and slight room for error as you can always cut off a small length before finalizing the cable, whereas you can't easily add more length after the fact.  This is all from memory, so double check everything as you do it and do what makes sense in your situation.

Next I chose to start by soldering my wires to the Neutrik plug.  This allows you to get a tight braid into the connector while also providing a small anchor for the braiding.  To do so, take apart the plug and set out all the pieces.  For my cable I decided to color code each channel - silver wire for left channel, copper wire for right channel.  You need to make sure that you solder the cables to the correct terminals.  The tip or center post of the plug is the left channel.  The ring or smaller outer post is the right channel and the larger outer post is the ground.  If you want to color code the wires, you need one of each color wire to the tip and ring posts and the remaining two different colored wires both to the ground post.  Either way:
  • Tip = Left Channel
  • Ring = Right Channel
  • Sleeve = Ground
Sorry for the poor image quality

Start by using a pair of wire strippers to strip away a short length of the wire sheath. Maybe half an inch. Not much. Once all the wires are stripped, you need to put them through the rear part of the Neutrik plug. Don't forget this. Also, one more thing before you continue; Don't forget to put the wires through the rear part of the Neutrik plug. Don't say I didn't remind you. ;)  You need to do this so you will be able to screw it onto the plug after it is soldered. If you're using a straight Neutrik plug don't forget to also feed the plastic insulator piece over the wires after the rear piece. Next, you can place the wires in a vice or "helping hands" or ghetto soldering contraption like mine (I've since built my own helping hands) to prepare for soldering. Leave the ends sticking out so you can "tin" them.

For those new to soldering, a few tips. Pun intended. Always keep the soldering iron tip tinned with solder. Don't let it sit without solder on the tip. This is bad. Just touch some solder to the tip as your iron is heating up and keep touching the solder to it until some melts onto the tip. Once it is melting onto the tip you want to keep the tip clean now and then as you solder by wiping it off on a slightly damp sponge or copper sponge cleaner and then add solder to the tip again. Also, only leave the iron turned on as long as you need it. If you do these things the tip won't oxidize (turn black). When that happens it won't allow solder to glob onto the tip any more and that's no good. So, now that the wires are being held with the ends sticking out, you can touch the flat side of your tinned soldering iron tip to the stripped portion of the wires on one side while pressing some solder against the opposite side of the wires. Let the tip heat the wires, don't try to rub solder onto the wires. As you do this the wires will heat up and the solder on the other side should be absorbed into the wires. Your wires are now tinned. This makes joining the components easier later.

Now that your wires are ready, you can feed the wires through the posts on the Neutrik plug with the orientation as described before. I like to bend the protruding wire a bit to keep it from sliding out of a post while you're soldering. Sorry for the lack of soldering photos, but it's hard to solder and take photos at the same time. Next, with the plug in the vice and the wires run through each appropriate post and slightly bent, place the soldering iron (tinned of course) on one side of one of the protruding wires. Make sure to have the tip wedged against the wire as well as the post so it is contacting both metals. Now place some solder on the opposite side of the wire also pressing it against both the wire and post. As the solder melts you can feed a little bit by pressing it into the hole where the wire protrudes. You don't need much. Just enough to fill the small opening around the wire. When you're done, remove the iron and the solder. You don't want to keep the iron on the post for too long. These plugs are usually rated for a certain temperature for only about 10 seconds on average. Any longer and you risk damaging the plug.

Once you've soldered each wire, use a pair of wire cutters and cut off the excess wire above where the solder has bonded the wire and post together. Once all of the wires have been soldered and cut, you can slide the plastic insulator over the wires and posts if you are using the straight plug. Next, put together the Neutrik plug. The right angle plug has a few plastic piece that you need to situate per the instructions that should have come with it. You will want to slide the main plastic piece over the post area and run the wires along the inside of this piece. Then place the smaller plastic piece on the other side of the wires and slide the rear piece onto the plug and screw it tight. If everything is together properly, screwing the plug together should cause the wires to be gripped in the plastic pieces so that it is held tight. If the wires don't fit well or it doesn't screw together easily, you can remove the small breakaway tab on the plastic piece and/or shave some of each side of the plastic to make room for the wires more comfortably. If you don't have a multimeter, at this point you should label each wire on the open end with tape as to which channel/ground it is. I just marked the wire sheathing with a sharpie using one dash for left, two for right and three for ground.

Once the plug is complete, you can place the finished plug in the vice with the wires facing you. Now you need to braid the wires. For the bottom of the cable, which is where we are starting, you need to do a four wire round braid. Once you reach the part where the wires split to each separate channel you can simply twist the wires. I measured the point at which I wanted the split by comparing my favorite earphones and using them as a reference. I placed a small piece of tape at that point so I knew when to stop braiding. The braiding is simple once you know the pattern, but for the life of me I could never recover from a messed up braid easily, so don't mess up. :-P

The method I used to do the braid is as follows. Start with the four wires spread apart a bit sideways. It doesn't matter which color you start with (unless you want a certain pattern), because you can arrange the wires at the split when you finish the braid. Now with the wires spread out, hold the left two wires in your left hand and the right two wires in your right hand. Start by passing the right-most wire underneath the two wires next to it and then wrap it around the middle wire. In other words, if the wires are labeled 1 2 3 and 4 from left to right, take wire 4 and run it underneath wires 2 and 3 and then wrap it over the top of wire 2 so that it ends up between wires 2 and 3. Essentially it now becomes wire 3 and the process starts again from the opposite side. Wrap wire 1 underneath wires 2 and 3 and than wrap it over the top of wire 3 and it should end up between wires 2 and 3. This wire now becomes wire 2 essentially, and repeat over and over switching sides each time.

I like to keep the braid snug but not tight. Too tight and the wire won't seem as flexible. Too loose and the braid can become messy. Once you have braided the cable to the point where it will split, you can neatly wrap some electric tape around the point where the split will be.  Just a bit and no wider than the width of the tape itself. Perhaps a two wraps or so. This provides something to keep the cable together nicely and for the heat shrink to grip to keep it from shifting.  Next, you want to slide some heat shrink tubing over the open end of the wires. I chose a size that was a bit larger than the four wires but not much and a bit wider than the width of the electric tape. Slide it down over the electric tape so each side of the tubing evenly extends over the tape. Take a heat gun or butane lighter and heat the heat shrink by waving the lighter back and forth from a few inches away. Start by waving the lighter quickly back and forth so you don't melt anything or overdo it. Start slowing down the waving motion until you start to see the heat shrink starting to shrink. As it shrinks you can rotate around and heat each side evenly. Once they heat shrink is evenly shrunk let it cool for 20 seconds before touching it. It should have shrunk so that the ends of the heat shrink are a little tighter past each end of the tape it covered. This will lock it in place, as heat shrink can and will usually slide over time otherwise.

No you can gently place the y-split section you just made into a vice or something to hold it. At this point you can use the labels you made or test the wires with a multimeter to determine which wires to route to which side. Set your multimeter to continuity mode (a little diode symbol) and touch one probe to the tip of the plug and then touch the other probe to each open wire until you find which generates a tone on the multimeter.

...This post in a work in progress, sorry for the long delay. I'm currently working on a better, more secure recable method directly to the driver. I will complete it as soon as I can. Hang in there! :-)

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