The Model 20 series CW TWT Amplifier has been designed to operate 25 watt traveling wave tubes over the 4- 18 GHz range. The High Voltage Power Supplies are modular DC-DC converter designs. The Power supply design provides superior stability for optimum TWT phase noise and spurious performance. The front panel 4-line vacuum fluorescent display, with 2 page modes, provides a monitor for the operating characteristics.