(!!!!) (Best Value Single) 10 Sylvania "engraved base" 1930's used/good (23ma)

10 Sylvania "engraved base" 1930's used/good - "10" etched on base 23ma Gm=1800   Vplate=300V Vgrid=-15V Good mA range 20-30ma Good Gm range 1700-2000    General Information (Filament=7V @ 1.2A, Vplate=220V, Vgrid=-7V, Iplate=25ma, Mu=6, Rp=6Kohms) (The VT-25 is built exactly the same as a VT-52, but the plate and grid are spaced  differently yielding ifferent Mu factors and plate resistance)