[Milsurplus] Re: BC375 805s for 211 modulators

Unserviceable but Repairable cosmoline at ba-watch.org
Wed Jun 8 07:44:36 EDT 2005


Was: More on BC375 Tube Subbing* 

211 a lo amp-factor (10) critter per '57 hdbk. 

805 is same.  But has plate cap which is no impediment in modulators.  
Just paint caps black & run poly wire to 'em behind the tubes.   EXACT
electrical swap.

838 amp factor not given there but fine grid-pitch makes them
look like hi-mu 811s or 572Bs.  And someone here proposed they might
be sub'd for 211s running at zero rather than neg. bias (as pot 1113
sets in BC-191).  So conditionally a good modulator 211 exchanger.

There were a blue mil 805s in surplus & outside of scarce T350XM, don't
know where they went.  838s were finals in giant shipboard 'Battle Announcer'
Stromberg built for Navy & fewer in circulation than 805s.

Anyway - Tempe place advertises these prices

    211/VT4C   $195
    805        $105
    838         $61

& DaveS sez Chinese 211 clones $30.  If ya gotta buy 'em, nolo contendere.

Note all are 10V 3.25A filaments.   Much needed with all series
resistors to get 'em going off 14 or 28VDC in a '191 or '375.

    'rm  

* for the dyslexic, consider "moron tube subbing"


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