The D/140/H is a standard hydrophone element combined with a signal conditioning amplifier.

The pre-amplifier is housed in either a stainless steel or nylon tube with an O ring sealed lid at each end.
The hydrophone element is moulded in polyurethane onto one of the lids whilst the other acts as a penetrator for the multi-core screened cable. Two of the cores are used for supplying the 24 volt power with the other pair providing the differential output signal.

The proximity of the amplifier to the sensor allows the signals to be transmitted down long lengths of cable (up to 150 metres) without suffering any degradation. The differential output also improves the signal to noise ratio and achieves a better performance at higher frequencies. The gain of the amplifier may be adjusted using links provided on the PCB.

Available without the pre-amplifier as an option for other special applications, for example a customer designed pre-amplifier board or the element used as a projector with the tuning and matching components sealed inside the housing.