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Re: OLD Tubes/Coils - filament power



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Dear People:

        Permit me to take this opportunity to suitably humble myself
        and confess my sins  (well, a few of them anyway).

        My advice to under-run the the filaments of transmitting tubes
        was ill-considered in the case (numerous cases) of tubes =not=
        having indirectly-heated cathodes.  I stand abashed.

        A =great many= medium power transmitting tubes of interest to
        Tesla coilers do not have indirectly-heated cathodes and ought
        not to be under-run.

        Oddly enough, very low-power receiving tubes (intended for
        battery-powered equipment) also lack indirectly-heated
        cathodes.

                                - - - - - - - -
        As an aside -- The tubes formerly used as horizontal sweep
                        amplifiers in tv receivers are excellent for
                        use in Tesla work.  They are moderate power
                        (perhaps 30 watts or so), may be paralleled
                        as described in an earlier post for greater
                        power (indeed this was done in high-end tv's)
                        and =do= have indirectly-heated cathodes.

                                  Contritely yours,

                                   Robert Michaels






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