Attached is a PDF that contains all the parts necessary for building a hydrophone. The parts on the list are from the following companies:
• Digikey
• Pacific Radio and Electronics
• Do It Best Hardware Center (I go to the one on York Blvd in Highland Park)
One thing to note. There are two type of cables listed for your reference. One is standard microphone cable and the other is a slightly smaller gauge coax video cable. You can use either one.