Abstract: The amplifier is intended for use in situations where a considerable distance separates the instrument (for example a piezo-electric transducer) to be monitored and the control room. The amplifier comprises a charge/current converter for converting the charge output of the instrument into a current signal, the charge/current converter being connected to operate as a high impedance current source, a current/voltage converter and a connecting cable connecting the current output of the charge current converter to the input of the current/voltage converter.