The S series of solid-state amplifiers includes four models for the 0.8-to-4.2-GHz frequency range. The model 15S1G4 delivers 15 W CW while model 30S1G4 produces 30 W CW, model 60S1G4 outputs 60 W CW, and model 120S1G4 generates 120 W CW. All versions employ a new design that delivers more than twice the power of older models while consuming less power. They also incorporate both USB and Ethernet ports in addition to GPIB and RS-232 interfaces. Model 15S1G4 can be expanded from 15 to 30 W in the same cabinet when higher power is needed. The highest-power version, model 120S1G4, is a portable, self-contained, air-cooled amplifier that is designed for applications that demand instantaneous bandwidth, high gain, and linearity. Push-pull circuitry is utilized in all high power stages in the interest of lowering distortion and improving stability. A digital control panel provides both local and remote control of the amplifier. The amplifier's low level of spurious signals and high linearity make it suited for use as a driver amplifier in testing wireless and communication components and subsystems. It also can be used with test instruments covering multiple frequency bands.