Please add a PCB with a preamp and impedance buffer for a piezoelectric element

[Supermagnum]

The problem with piezoelectric and contact mics is that they are not well matched to typical audio inputs.
The reason why these devices often sound tinny is because the piezo sensor presents its signal through a series capacitance which is small, typically 15nF or less. When wired to a normal 50 kilohm line input this forms a 200Hz high-pass filter, which eliminates the bass.
Because the piezo disc has a very high impedance (1 MΩ typical), it should be buffered to avoid possible impedance mismatch with an existing audio system. This circuit acts as a impedance buffer, and some amplification does not hurt as long as it is around 40dB. A nice opamp is LME49724
I have created a pull request for my version of the described circuit.

[Supermagnum]

Suggestion:
https://github.com/Supermagnum/double-gain
I have built and tested it,- it works.
I used marine silicone inside the metal box that houses the piezoelectric elements.
The PCB may be converted to SMD to conserve space.
Finding op amps with minimal self noise and minimum power usage is no easy task, SMD alternatives: LT6234,LT6231, THT: NJM2122D