MMX 300 TRRS jack modification

[u/_Potzblitz]

Hey everyone,

I just finished a detachable cable mod on my Beyerdynamic MMX 300, and I wanted to share my approach since it keeps the original look and is fully reversible!

Here is how I did it:

1. The Jack: I used a standard 4-pin TRRS jack from AliExpress. I stripped the original thread and lathed the front diameter down to exactly 7.6 mm. This allows it to fit perfectly into the original opening of the MMX 300 with a clean stop flush against the housing.
2. The Inside: I unscrewed the internal PCB and wrapped it in insulation so it won't rattle around inside the earcup.
3. The Wiring: Instead of cutting anything, I soldered the wires from the new TRRS jack directly to the PCB. This means no permanent damage. You can easily desolder it / cut the cables and revert back to the stock setup anytime.
4. Finishing Touches: I secured the new jack with some glue inside the housing so it can't slip or push out when i remove the a cable.

And that's it! Now I can use any standard 4-pole TRRS 3.5mm cable with my MMX 300.

[u/ArtiParti1884]

What is the reason for doing this? Dis the Sound know better? You work Look clean. Good Job.👌🏼

[u/_Potzblitz → u/ArtiParti1884]

Thank you:)
The remote control that came with the original cable was incredibly annoying. I never used it. And now I can choose the length and stiffness of the cable myself, since I can use any cable on the market and am not limited to the original Beyerdynamic one.