When a load requiring a very fast rising current is fed from a flux-compression generator, it is necessary to introduce a conditioning circuit in order to reduce the rise time of the generator output current substantially. The final stage of this circuit will include a plasma erosion opening switch, which is the fastest known opening switch for use at the current levels involved. This paper presents results obtained during the development of a novel two-stage conditioning circuit and compares the experimental performance of the circuit with results provided by a computer simulation. A time compression of the rise time of the currents from microseconds to less than 100 ns was obtained, representing a 40-fold increase in the corresponding signals.