tubes williamson

Posted on Feb 6, 2014

A discussion of the Williamson Amplifier should be first preceded by an overview of its context in the evolution of the vacuum tube and its application to high fidelity audio reproduction. Transformer coupling was widely used pre-war because it was simple and effective. It was widely used throughout WWII and later - particularly for public address amplifiers and radio transmitters.

tubes williamson
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But transformers were expensive, used scarce and expensive raw materials, and performance was generally limited by the transformer characteristics to a frequency response flat from about 20-20, 000 Hz at best and 100 to 5, 000 Hz at worst. Distortion was high due to the use of transformers (low quality by modern standards) and no negative feedback of any kind. Hum, noise and microphonics would have been barely tolerable. Loudspeakers were improving at a rapid rate and their frequency response capabilities were creating listener awareness of the limitations of the amplifiers of the era. This was a time when large numbers of military personnel were being returned to civilian life and the British economy was in a state of new growth and development. There was interest, motivation and social approval for people interested in good quality audio to think about it and, if possible, improve their pre-war equipment - by then at least seven years old and most likely much older (a long time in those days). Pre-war valve audio obviously did not include the significant advances made in vacuum tube technology and componentry throughout the world during the war years, so the time was ripe for consumers to upgrade to the benefits of that technology. Throughout the 1930`s, British valve manufacturers had faced stiff volume and price competition from imports, sourced primarily from the USA. There was much bad blood between the British...

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