Abstract: A dual power source output amplifier comprises at least one pair of first and second input voltage sources of like polarity, operating at low and high voltage magnitude levels respectively relative to one another, and selectively operably coupled to an output stage for driving a load, for example a convergence yoke coil, in low and high voltage modes respectively. The first voltage input source is coupled to the output stage in the low voltage mode. A circuit for directly sensing the output voltage couples a biasing voltage level to the output signal for generating a high voltage demand control signal which varies directly with the output voltage. A switchable voltage regulator couples regulated high voltage from the second voltage input source to the output stage in the high voltage mode, responsive to the high voltage demand control signal. The output stage operates substantially linearly in both voltage modes.