OE5JFE KX2/3 DIY Mini Microphone PCB with 3D case

Hello everyone,

After several itterations I am happy to share my version of a small microphone for the KX2/3.
Fully aware that Adam @K6ARK has shared something very similar just some month back.

But I wanted to my own take on this matter.
Skills that I developed was simple PCB design using a well know Chinese PCB supplier with various error in planning and execution but here we are:

The “handle” on the left side is used with some shrininking tube as strain relief.

I use a 4 ping TRRS connector on the radio side. On the mic cable I add a ferrite choke - who knows it might help hi. It is a 90° angled extention cable that I just cut to about 80 cm lenght.
The mic capsule is not placed like shown but pointing to the side. This perfectly centers it.
Audio tests via the monitor function on my KX2 sound excellent.
All SMT parts (so without the capsule) can be ordered already assembled on the pcb. I hand soldered them in this version.

The 3D printed case is fixed with 2 shrinking tube pieces so in case it is needed one can open up the case.

And here the assembled version:

I am not planning a mass production but will work on the documentation and will share so that everyone can make their own version.
If enough interest is shown I will organize a small group buy. Contact me via private message here on the Reflector. Thank you.

73 Joe


Hi Joe

That looks great. I did something similar when my MH3 broke:

To make PCB manufacture cost effective, I designed the PCBs to be snap out:

I had to have 50 PCBs made and stuffed (minimum quantity) so I’ve had them up for sale on eBay:

Anyway, here’s the guide I wrote for tweaking the KX2 for different Electret condenser microphone modules.