This section is dedicated to an overview of the electronic tubes found by the first electrical sound equipment (Radio, TV, Amplifiers) present in Piedmont in the area between the cities of Turin and Asti in the 20th century.  

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Below are some images with references. For further information, see for example the dedicated museum (also online) located in Switzerland.​

https://www.radiomuseum.org/dsp_searchtubes.cfm

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