This low frequency amplifier series can be used in conjunction with other amplifiers from the Teseq range to cover the entire frequency range from 10 kHz to 40 GHz with convenient frequency break points allowing you to optimise the power level in each range. The Class A design ensures a high reliability, low distortion linear performance across the frequency range. This design also ensures that the amplifier series will continue to operate at full power even when presented with an open or short circuit at its output. The units are powered from a switched mode power supply for high efficiency, high power factor and wide voltage range operation. Air-cooled with integral fans, and are protected against faulty cooling by excess temperature sensing. A safety interlock connector is provided, which the user can short circuit to ground, to put the amplifiers into standby mode. Front panel indicators are provided to indicate over-temperature and rf interlock operation.