(!) (Single) 37 Silvertone smooth plate used/tests like new 1930”s 1 top mica is folded down (7.1ma)

37 Silvertone smooth plate used/tests like new 1930”s 1 top mica is folded down (see photo) in white box

7.1ma

Gm=1000

Test parameters:

Vplate=250V

Vgrid=-18V

Iplate good range 6.5-8ma

Gm=1000-1100

(Filament=6.3V @ 300ma, many think the 37 sounds better than the 76)