Abstract: The low noise parametric amplifier disclosed is a non-cryogenic non-redundant plural stage unit with excess gain such that failure of any one stage results in only minor degradation of signal-to-noise ratio. While the amplifier is of general application, it is specifically intended for use in the receiver of an unattended earth terminal of a satellite communication system. In this environment, reliability is achieved by employing a plurality of cascaded, modular parametric amplifier stages. Each stage includes a varactor diode, a pump circuit with its oscillator, a bias circuit, and temperature stabilizing circuitry employing a Peltier junction. The stages are connected to a multi-port circulator by quick disconnect couplings which permit the modular amplifier stages to be removed and replaced without any interruption in the operation of the amplifier.