When properly installed, the pickups have no impact on the acoustic sound of a board-mounted or celeste kalimba. A few times, I have seen kalimbas with loose pickups which rattled. You can fix this by tightening the nut on the pickup jack, or possibly by using a bit of glue. Box mounted kalimbas with pickups have a subtle effect. You make a “wah-wah” sound by covering and uncovering the sound holes. The pickup jack is one more sound whole. SO, the “depth” of the “wah wah” sound is slightly diminished when you have a pickup – this is like a 10-15% effect.

Here is another thing I have seen a few times – the jack has a long thin piece of metal that reaches around the guitar cord plug and touches the tip of it, and that piece of metal can sometimes vibrate like a kalimba tine. Or almost like a kalimba tine. What happens is one particular note on the kalimba will excite that arm to vibrate, and it will buzz. So if you have a crazy buzz that cannot be fixed by any of the regular methods, stick your finger inside the sound hole and touch (ie, deaden the vibrations of) the metal arm near the jack and see if that doesn’t fix the problem. If so, try fiddling with it, bending it a bit, or changing its orientation.

original text taken from kalimbamagic.com