The Lowther Journal ¡ 11 December 2025
The PX4: Quintessentially British
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.
Peter Snell
Lowther Loudspeakers ¡ 2 min read
A British Invention
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.
From Commonplace to Coveted
For decades, the PX4 was part of everyday listening. As transistors took over, production declined, and the valve that once powered a nationâs 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.
Why PX4 Matters to Lowther
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.
Built the Lowther Way
Our PX4 amplifier is not a reproduction; it is a continuation.
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Transformers are wound in Dorset.
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Chassis are engineered in Birmingham.
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Assembly is point-to-point, preserving both authenticity and sonic integrity.
Each amplifier is made to order, crafted to stand alongside our loudspeakers as part of a complete system without concession.
A Living Legacy
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.
Lowther for Life Exclusive Price
Available to order now directly from Lowther with your Lowther for Life code. Enter this code at check out: V4X6YCQ3NVA5
Other links
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Acousta Quarter Wave - Our classic folded horn cabinet refined for today. Natural clarity, strong bass for its size, and suitable for a wide range of rooms. Handmade in Great Britain.
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Edilia - A modern development built around a full range PM7A with a controllable bass system. Designed for real rooms with easy placement and a balanced presentation.
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Philharmonic Collection - Our most refined fixed range of drive units with military standard metalwork and carefully treated cones. Built for those who want the fullest Lowther experience.
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Sinfonia Collection - Premium diaphragm treatment and enhanced assembly techniques. A clear improvement in stability, detail and balance for builders and cabinet owners.
