newbie: Piezo as Underwater Contact Mic, Z-Diode?

[todoke]

Hello, this is my first post here.
I'm starting with electronics and don't have so much knowledge yet.

I want to make some underwater recordings and found that piezos can be used well for this. So besides the huge different possibilities to build it mechanically, I'm also unclear about how to do it electronically.

I guess it would work with just the piezo itself, connected to a digital field recorder.

But I want to protect the recorder against voltage spikes and thought of using a Zener / Z-Diode for this.
Which maximum Voltage should be ok for a field recorder?

Next, I'm wondering whether the the signal will be too noisy if I don't pre-amplify it. Batteries seem unpractical for the sealed case and phantom power seems risky to me. I want to use it with just 5 m of cable for now.


I would appreciate any help on this to get me started.
Thanks!