→External links
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* [http://www.tubebooks.org/ Tubebooks.org]
* [http://www.geofex.com/tubeampfaq/taffram.htm Musical Instrument Tube Amp Building, Maintaining and Modifying FAQ]
* [https://web.archive.org/web/20090513025236/http://www.jacmusic.com:80/html/articles/ericbarbour/howavacuumtubeworks.html How a vacuum tube works] by Eric Barbour
[[Category:Vacuum tubes]]
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