Can anybody exolain how does work the zener used in the middle of the filament trnsf tap. I mean how it electrically works Thanks EA1KI Miguel -- FAQ on WWW: http://www.contesting.com/ampfaq.html Submissions: amps@contesting.com Administrative requests: amps-REQUEST@contesting.com Problems: owner-amps@contesting.com Search: http://www.contesting.com/km9p/search.htm