I am trying to make a pocket size mic, preamp, amp, and speaker combo, that can be placed on a reasonably resonant wooden floor that will pick up and amplify tap dancing. As is so often said in life, it is easy to make one that works, but it is difficult to make one that works well.
A piezo disc into a 2N5457 JFET as a high impedance preamp, and an LM386 chip as an amplifier, output to the little speaker, kinda works. (Instructions are in various places on the internet.) At least it makes sounds like someone doing something with their shoes on the floor, but a tap dance amplifier, it is definitely not. Same thing when it is setting on the sounding board of a piano: like you are playing thru some weird effects.
So I ordered the Cortado mic and preamp kit today and am excited about soldering it up and seeing how it works. For the money, it will have to be better than what I’ve put together so far. It seems like properly coupling the contact mic to the floor will take a lot more trial and error to get a decent sound. I am looking forward to learning!