Leafcutter John shares the steps he took to build a phantom-powered underwater mic from a steel can (looks pretty classy!) –
I decided to house the pre-amp in the same enclosure as piezo elements (to avoid noise entering the circuit). The challenge here is to find a decent enclosure. As the piezoâ€™s and the pre-amp will be underwater they need to be inside something water-tight.
After a few experiments, I found you can quite easily solder steel food cansÂ together using a regular soldering iron and electrical solder. It works for water pipes so It should be water-tight in this case. Â NOTE:Â aluminumÂ cans will not work at all well!!! Get out your magnet and find some steel ones!