The Answer to “Why PX4?” Because it is British. Because it is authentic. Because it is the valve that best reflects Lowther’s pursuit of truth in sound.
In the late 1920s, the Marconi-Osram Valve Company introduced the PX4. Designed and built in Britain, it was one of the first directly heated triode power valves. Its clarity, linearity, and unmistakable character soon made it the foundation of high-quality amplification in British homes and studios.
For decades, the PX4 was part of everyday listening. As transistors took over, production declined, and the valve that once powered a nation’s radios and amplifiers became rare. Today, surviving originals are treasured for their sound and for what they represent: a uniquely British contribution to the history of hi-fi.
At Lowther, every choice is intentional. While the 300B, designed by Western Electric in the United States, has become the familiar name in valve amplification, the PX4 belongs to our heritage. To choose the PX4 is to continue a British tradition of triode design — one that aligns with our philosophy of minimal compromise between listener and music.
Our PX4 amplifier is not a reproduction; it is a continuation.
Each amplifier is made to order, crafted to stand alongside our loudspeakers as part of a complete system without concession.
The PX4 is more than a component. It is part of a lineage that shaped how music was first heard at home. By developing the Lowther PX4 amplifier, we honour that history while carrying it forward — ensuring that the voice of this British original continues to be heard in the highest fidelity.
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