* http://www.triodeel.com/
* http://www.londonpower.com/
* http://www.firebottle.com/ampage/
* http://users.aol.com/bluemuse/ampeg.html
* http://www.eden.com/~keen/
* http://www.gnt.net/~nps/tubeamp/index.html
* http://www.wcug.wwu.edu/~jamie/schems.html
* http://www.hyperreal.org/music/machines/Analogue-Heaven/email.html
* http://www.gnt.net/~nps/tubeamp/index.html