Overview & Features
Ground cable for hydrophone AHK-ERD10, length 10 meters.
The ground cable is used when a static hum occurs when recording. This can happen if there is strong magnetic interference at your location.
Water absorbs electrostatic radiation. Therefore, electronic devices known to emit electromagnetic radiation should be kept away from the water in which they are to be absorbed. (switching power supplies, fluorescent lamps, CRT screens or television sets, ...)
The ASF hydrophone has a high gain preamplifier and therefore also amplifies any electromagnetic signals that the piezo sensor detects. However, this can be easily remedied by making an electrical connection between the body of the recorder and the water that the hydrophone touches.
The best way to do this is to use the AHK-ERD10 cable, which you connect to pin 1 of a free XLR input and hold in the water near the hydrophone. But any electrical connection between the ground of the recorder and the water will do and should eliminate any unwanted noise you may experience.
CAUTION: Never do this if you are recording from a boat and your mixer/recorder is connected to the ship's electrical ground. If you experience induced mains hum, ALWAYS disconnect the ground of your mixer/recorder from the ground of the power supply (e.g. using battery power) before connecting the audio ground to the water.
