PURPOSE: To match the power amplifier with a broad impedance load, by connecting each output of an arbitrary number of SEPP power amplifier to the primary windings of an output transformer and providing taps for load impedance matching for the secondary windings.

CONSTITUTION: The primary windings of an output transformer 11 consist of a plurality of low impedance windings corresponding to the number of SEPP power amplifiers, the secondary winding has various impedance taps matched to various loads, the output of each SEPP amplifier amplifying an input signal is given to each primary winding, the outputs are synthesized and applied from the secondary winding to the load. A part of the outputs is negative-fed back via a negative feedback resistance to improve the stability. Since the SEPP amplifiers have a low output impedance, the surge voltage is lowered, no damage is given to transistors and since the power amplifiers are divided into several units, the flexibility can be provided.