[Amps] filament supply D.C or A.C

[d.cutter at ntlworld.com]

This might give you a clue, but not the full answer:  a lamp manufacturer published a treatise on this subject and concluded that ac was better for life expectancy.  Something to do with migration of electrons from the surface of the filament, with dc it was all one way and eventually led to break down; with ac there was little net migration.  They showed electron micro photos.  I have a mental picture of the lamp brochure, but can't remember who.

David
G3UNA
> 
> From: eran <erniaba at netvision.net.il>
> Date: 2008/02/13 Wed PM 12:11:51 GMT
> To: amps at contesting.com
> Subject: [Amps] filament supply D.C  or A.C
> 
> Looking for reliable information regarding filament supply to amplifier
> tubes. What are the pros and cons for  D.C or  A.C volts.
> 
>                                                       Thanks and 73s Eran
> 4X1MO
> 
> 
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