Preamped Hydrophones

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Submitted by dave on

I've built up a hydrophone using one of the new piezo preamp boards, and tested it against my last hydrophone.

Not the most scientific test, but demonstrates a bit what's going on.

== Construction ==
Hydrophone Construction 1
Hydrophone Construction 2
Hydrophone Construction 3
Hydrophone Construction 4

== Mic Inputs ==

To keep things constant, the first tests use the mic input for both piezos. The gain was boosted on the non preamped piezo by 28dB to roughly match levels.

This is short section of some scraping and banging noises recorded with the hydrophones dipped into a metal pan balanced on a chair. There's far less noise on the new one after normalisation

Old Hydrophone (mic input):

New Hydrophone:

== Line Input ==

Note: everywhere I say "Line Input" here, I actually mean "Instrument Input"

Since the mic input is inappropriate for piezos, the second test uses the line input, as I'd previously been doing.

Here, the level is approximately the same (according to the gain setup on the Saffire).

This shows a lot more noise on the unamped piezo, and also a loss of treble. There's some strange popping on the line input piezo - not sure what that's about.

Old Hydrophone (mic input):

New Hydrophone:

Tags: 
piezo preamp
hydrophone
testing
audio electronics
Project Type: 
Sound and Music