https://www.preservationsound.com information and ideas about audio history Wed, 24 Apr 2013 11:12:23 +0000 en-US hourly 1 https://wordpress.org/?v=6.9.4 https://www.preservationsound.com/exactly-what-do-all-those-tubes-do/ https://www.preservationsound.com/exactly-what-do-all-those-tubes-do/#comments Wed, 24 Apr 2013 11:12:23 +0000 http://www.preservationsound.com/?p=6414 Several things, actually.  Check out this great c. 1943 promo film produced by Westinghouse.  Thanks to TW for alerting us to this clip.

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