One of the drawbacks of by KX1 is the need to carry headphones since the rig doesn't have an internal speaker. So I decided to build an external one. The case was designed using OpenSCad. The speaker device also functions as a powerpole splitter. This saves me one converter from powerpole (which all my rechargeables have) to the jack used by the KX1. And it allows me to connect another device to the battery, for example a mobile phone charger.
Several tries where necessary until the design worked.
Once the case design was ok, assembly was a snap.
Finally, I had to replace the NF amplifier. I used what I found in my spare parts box when building the first one. The amplifier IC was a TDA2003 - which had a quiescent current so high that one could boil eggs inside the case. Lesson learned: Always read all parts of the data sheet. The second version uses a LMF386-4 and works great.
Now the external speaker is a trusty companion when working outdoor with my KX1.
