1. A MAGNETIC BRIDGE AMPLIFIER FOR PROVIDING A HIGH CURRENT GAIN OUTPUT TO A LOAD FROM LOW CURRENT LOW FREQUENCY INPUT SIGNALS COMPRISING, A FOUR-ARM, FOUR-JUNCTION BRIDGE HAVING A DRIVING OSCILLATOR CONNECTED TO TWO OF SAID JUNCTIONS AND A LOAD CONNECTED TO THE OTHER TWO OF SAID JUNCTIONS, A PAIR OF SATURABLE REACTOR CORES EACH HAVING A CONTROL WINDING AND A LOAD WINDING, SAID CONTROL WINDINGS CONNECTED IN SERIES, INPUT SIGNAL MEANS CONNECTED IN SERIES WITH SAID CONTROL WINDINGS FOR RECEIVING LOW CURRENT LOW FREQUENCY SIGNALS, A PAIR OF UNIDIRECTIONAL CONDUCTING DEVICES EACH CONNECTED IN SERIES WITH A RESPECTIVE ONE OF SAID LOAD WINDINGS, A RESISTOR AND A CAPACITOR CONNECTED IN PARALLEL SHUNTING EACH OF SAID UNIDIRECTIONAL CONDUCTING DEVICES, ONE OF SAID LOAD WINDINGS, UNIDIRECTIONAL CONDUCTING DEVICES, AND PARALLEL RESISTOR-CAPACITOR SHUNTS DEFINING A FIRST ARM OF SAID BRIDGE, AND THE OTHER LOAD WINDING, UNIDIRECTIONAL CONDUCTING DEVICE, AND PARALLEL RESISTOR-CAPACITOR SHUNT DEFINING A SECOND ARM OF SAID BRIDGE, A PARALLEL RESISTOR AND CAPACITOR DEFINING A THIRD ARM OF SAID BRIDGE, AND ANOTHER PARALLEL RESISTOR AND CAPACITOR DEFINING A FOURTH ARM OF SAID BRIDGE.