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Re: Filament Brightness different in matched quad?

The term Matched should refer to electrical measurements and not cosmetic appearance. The degree of brightness associated with filamemts is a factor of how much actual filament structure is visible outside of the enclosing cathode sleeve. IOW, if more (or less) of the filament is exposed outside of the cathode, the brighter (or dimmer) the filament will appear. But since a vacuum tube's purpose is different than that of a light bulb, the amount of filament glow seen is of no consequence to tube operation; the sole purpose of the filament is to heat the cathode to electron-emiting temperature - so a somewhat better evaluation method than looking at it would be to touch the tube & discover if it burns your finger.


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  • Re: Filament Brightness different in matched quad? - Ron Oehlert 21:49:54 07/30/06 (0)


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