Contact microphones can be directly applied to resonators. In this case a microphone is attached to a resonator body under the bridge. A further microphone is glued on the bottom of the harmonic resonator. On both piezo a thin layer of wax is applied to dump vibrations. In this way we obtain a stereo resonator where the upper microphone collects high frequencies and the lower one the lower. Adjusting the volumes of the preamp one can build the final timbre of the instrument.

If we want to use small carriable music boxes we need to build a simple microphone preamp. After different trials we found a decent solution

The schmatics of the circuit are shown in the picture

We apply the contact microphone on the resonator and connect to the preamp and test the sound quality.