Replacing broken Beyerdynamic MMX 300 cable

DISCLAIMER: please, follow this guide at your own risk. Several steps may end in a p0wned pair of cans if not done properly. And I’m not willing to be held responsible should that happen ;).

Introduction

Around 2014, I bought what I considered was a very nice, polivalent and not so expensive audio setup for my personal use. It was based around my computer and consisted of two items:

• Asus Xonar Essence STX soundcard
• Beyerdynamic MMX 300 (1st Generation) headset

For me it opened a new dimension in music listening experience. But after some years the cable started to broke around the area where it enters the left can:

So it was obviously time to do some repairs. Initially, I investigated the idea of converting the connection to a removable one (as in the MMX 300 2nd Generation), but I discarded the idea because of the complexity of finding a 5-pole connector for audio, the right cables and the inherent difficult of physically modifying the cans by drilling a hole.

Very conveniently, Beyerdynamic has an online parts store. Sadly, the required part for my little repair was no longer sold there. Anyway, after looking in their authorised retailers, I found the one for my area (Madrid, Spain), contacted them, and three days after I had the part delivered (all for around 30€):

The repair process

So, on to the repair process. The setps are the following, it’s not a difficult process, but it’s important to be cautious. A steady hand and some soldering experience are important as well.

1. Remove the left can ear padding. Just by mere pulling with the fingers:

   

2. Remove the plastic ring that keeps both the protecting foam and the actual speaker in place. I had to use a flat screwdriver and gently pull, but be careful not to dent or even broke the piece:

   

3. Extract the speaker from the can to expose the PCB with the connections. Gravity itself should be enough to perform this task:

   

4. Remove the metal clip retainer that is in the inside part of the can fixing the cable in place (bottom right in the following picture), and desolder the cables from the PCB. Before desoldering anything, the PCB should look like this:

   

   Detail of the connections:

   • 1st, red: audio
   • 2nd, blue: audio
   • 3rd, copper: audio (ground)
   • 4th, copper: mic (ground)
   • 5th, empty
   • 6th, white: mic

   Other connections (you should not touch these):

   • L-, L+: left speaker
   • R+, R-: right speaker

   Please, be very careful not to spill soldering material while desoldering/soldering to the neighbouring connections to not to short anything.

   Desolder everything in the first list, and get rid of the cable.

5. Now the real deal, at least for me. Insert the new cable and solder everything in the same order. I found it was easier to do this before securing the cable with the metal retainer. For me, the technique was to hold the cable with the right hand and push it against the soldering pad, and then, with the soldring iron in the left hand (I’m right handed) warm the soldering pad until the the soldering material melted and the cable sunk into the material. Then release, breathe, and go for another round.

   This is what I came up with (yeap, I burnt the mic cable cover):

   

   I’m not the best solder in the world, or event a good one by any means, but I did a fair job. And the most important: it works!

6. And to finish, just do a quick test to verify everything worked, put the retaining clip back in place and to the steps 3, 2 and 1. 1 in reverse could be somewhat difficult, I helped the process with my small flat screwdriver (much better than force-stretching the pad back in place).

Before/after

So, I went from this mess:

To this magnificent, almost factory new, state:

And now it is just about enjoying that feeling of fixing something by yourself…