Important note

These instructions have been lifted from the printables.com page which contains the STL files and BOM you’d need to print your own case.

Microphone element polarity

There are two elements available; the “Standard (CMA-6542TF-K)” (shown bottom) and “-24dB (AOM-5024L-HD-F-R)” (shown top).

Below is a picture which shows the polarity of the two microphones, as a guide.

The two microphone elements on squared paper, with hand-drawn arrows marking the +ve and -ve pads on each: the green -24dB element at the top and the standard element at the bottom, its -ve pad being the one with the traces

TRS socket connections

A 3.5mm panel socket next to a TRS plug on squared paper, with hand-drawn lines showing which socket lug connects to the tip, ring and sleeve of the plug

Cut wire and solder mic and switch to jack

Cut four pieces of wire to 30 mm in length and strip 3 mm of insulation from each end. Solder wires as shown in images below.
Note “ground” traces on mic element. Connect that pad to the ground lug on the 3.5mm jack. Also note which switch lugs to use.

Type K

Supported radios:

Elecraft KX2 & KX3
BG2FX FX-4CR
HF Signals sBitx & zBitx

Hand-drawn Type K wiring diagram for the standard element: the element’s -ve and +ve pads and the push switch wired to the lugs of the 3.5mm jack

Hand-drawn Type K wiring diagram for the -24dB element: the element’s -ve and +ve pads and the push switch wired to the lugs of the 3.5mm jack

Type Q

Supported radios:

QRP Labs QMX & QMX+
(tr)uSDX
uSDX (not cloned 4-pin mic variants)

Hand-drawn Type Q wiring diagram for the standard element: the element’s +ve and -ve pads and the push switch wired to the lugs of the 3.5mm jack

Hand-drawn Type Q wiring diagram for the -24dB element: the element’s +ve and -ve pads and the push switch wired to the lugs of the 3.5mm jack

Test microphone

Plug the mic into your rig and test. Check Elecraft manual for settings. You may need to change menu items for PTT bias.
If mic does not work, try swapping the wires connected to the outer lugs of the jack and test again.

Install jack, switch, and mic into “Bottom” half of case

Carefully press jack into place. Note ground lug position, centred in printed slot on base.
Press switch into place, taking care not to damage lugs.
Press mic element into place, taking care not to damage wind screen on front (not critical).
Tuck wires into centre channel of bottom case ensuring wires will not be pinched in top cover.

The bottom half of a black printed case with the 3.5mm jack, push switch and mic element pressed into place and the red wires tucked into the centre channel

Snap on top cover

Ensure the wires are tucked in and will not be pinched, and snap on the top cover. Tighten the nut on the jack to finish the build.

The finished microphone in a black printed case with the push button on top, next to a 3.5mm cable

Now, get on the air and have some fun!

This work (text and physical case) is licensed under a Creative Commons (4.0 International License) Attribution-NonCommercial-ShareAlike.

Permission granted from Adam, K6ARK to reproduce this text and the kit in this store.