Alternative KX2 microphone?


I remember reading a post where someone mentioned a modified microphone (Baofeng?) for use with their KX2. I haven’t been able to find it but would welcome the details.

Which model of microphone was adapted and what modifications were needed. I do not need the up and down frequency function. Any ideas?

The MH3 didn’t work on Sunday (GM/ES-067) and this is to have a spare ready next time.



Google said W0CP: Adapting a Two Pin Speaker Mic to the Elecraft KX2 and KX3 (Kenwood, Baofeng, Pofung, etc)

No need to build anything. I was drawing out the diagram to build something, then realized I’d just drawn a stereo-to-mono splitter. So I tossed the drawing, bought a splitter off the shelf, and wrote this blog post.

For an electret mic, the splitter also gives cleaner mic bias, because it splits out the logic bias, which isn’t filtered. As another bonus, the right channel gives you a PTT jack.



While they do not have the up/down function, I’ve used a Baofeng (63g), but moved to a lighter Retavis (51g). Got both on amazon IIRC. Both work great per reports. There are others that are not hand-held type,and then there is obviously the KX2 built in mic. Once you open it up and line up with Elecraft wiring diag, simple to set up.

Mark / K6MTS

I suggested this mic a while back:

Barry N1EU

Thank Barry,

I remember your post. Do you have details of what modifications you did to get it working?




here is another option
I have one, but never used other than testing that it works.

73 Gavin


Thanks Gavin,

This is the type of thing I am looking for.

I note that hamgoodies have “… taken a generic speaker-mic, removed the speaker and re-wired it for the KX3.”

I have a KX2 and I have two suitable microphones (or with suitable plugs) to rewire. It is the details of the rewiring I was seeking before I dived in and opened up the generic mics to get started. However, maybe I just need to get started!



No modifications, plug and play.

I use the following mic for my KX2:

With this mic you can save even more on weight. Of course it has no PTT, you have to use the TX button on the KX2. For my occassional excursions into SSB this is fine.

Heinz, OE5EEP

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Thanks Barry,

I had to modify the speaker mic you posted (bought from 409 shop) to get it working with the KX2. Disconnected the speaker, wired the electret circuit to the sleeve and tip wires, then wired the PTT switch to the ring 1 and 2 wires. I also had to isolate the PTT switch from the circuit board to get it to work. Tested with a QSO on 20m yesterday evening so success.



Thanks Heinz,

if I had seen this option before I ordered the “Speaker Mic for BAOFENG UV-3R UV-100 UV-200” I would have used it. Might order one as a back up anyway.

Many thanks



Same here, in fact I haven’t even tested it yet. However, at 15 pounds it struck me as excellent value.

Thanks Matt,

the unbranded speaker mic that I modified cost less than half of the hamgoodies fist mic. It is also 54 grams lighter (MH3 weighs146gms compared to 92gms). Note that I am using a KX2 not a KX3 and there appear to be differences in which microphones will work with which radio.

Also, I have had some problems with the microphone supplied for the KX2. Those problems appear to be resolved but the result is that I am now keen to carry a spare mic.

Thanks and best wishes.



just to report that the alternative microphone worked perfectly using 40m band on GM/WS-196 (Beinn a’Chapuill) on Saturday afternoon, despite the contest stations. Thanks to chasers and all the good advice, worked a treat.



I made an adapter and I am using a Heil Kenwood HT boom mic. Weighs (with adapter) about the same as the stock mic.


It may have been my old thread possibly…

Glad you have found a solution. The original microphone uses an electret, but with a series HPF (High Pass Filter) in series to boost the upper audio response in the MH3. I found, even using the inbuilt DSP EQ that I couldn’t offset the over-emphasized bass that the audio appeared to have with no high pass filtering in-circuit. The above thread explains what I did to implement the same filter used in the MH3.

I strongly suspect the KX2 is the same. Given that, essentially the circuitry and audio DSP are almost identical in both radio designs…


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Thanks Jonathan,

The speaker mic suggested by Barry didn’t work when it arrived and the PTT started the KX2 scrolling through the band, 14MHz was where I tested it. I rewired the mic as mentioned above.

I didn’t get any reports of bad audio last Saturday on the field test, but there were many contest stations so perhaps it wasn’t a fair test. Might just be my squeaky voice!



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Today i built myself a cheap, small and lightweight microphone for the KX2 … seen on the videos from @ZL4RA and @K6ARK and recently brought up on this thread:

It turned out to be simple soldering work that was well within my capabilities :slight_smile:

Adjusting MIC BIAS, MIC BTN, MIC GAIN and TX CMP on the KX2 … it seems to work just fine. 121g less weight to carry and more space in my backpack for other things!

73 Martin, OE5REO


I use a set of Sony MDRXB50AP headphones with the largest replacement silicone earbuds I could find (better isolation) and a “Headphone 3.5mm Splitter Mic Cable”. Both are available at Amazon. I tweaked RX/TX equalization, set TX Comp to 20, and Mic Gain to 55. When I transmit, I hold the mic close to my mouth.

The combo is extremely lightweight, RX audio is strong and clear, and I get good audio reports from the remote stations.