Linear A

About the Linear A

The Tom Evans Audio Design Linear A is a high-end stereo valve power amplifier using a hybrid architecture: low-noise solid-state integrated-circuit input and driver stages feed an output stage built around four EL84 power valves per channel. The valves operate in a parallel, single-ended, Class A, ultralinear configuration intended to provide triode-like linearity with substantially more output power than a conventional single-ended triode amplifier. The amplifier is designed primarily for loudspeakers of approximately 89 dB/W sensitivity or higher and loads of at least 5 ohms. Later Linear A MkIII versions add upgraded input circuitry, enhanced power-supply filtering, Lithos 7.5-series regulation, improved output transformers, copper speaker binding posts, and user-selectable global feedback. Published specifications vary by version and source; figures below distinguish commonly reported original/earlier specifications from MkIII details where possible.