(!!) (Pair #3) 56 Sylvania black plate NOS 1940”s branded Western Electronics 1940”s one tube has slightly tilted glass (5.2ma and 5.5ma)

1 pair) 56 Sylvania black plate NOS 1940”s branded Western Electronics 1940”s original boxes, 4 metal prongs on top mica, same internals

1 tube) 5.2ma Gm=1400

1 tube) 5.5ma Gm=1500 slightly tilted glass – see photo

Amplitrex Test:

Vplate=250V

Vgrid=-13.5V

Iplate good range = 4.5-5.5ma

Gm=1400

– Inspire LP-27A