6b4g tube Sylvania power black plate engraved valve 6b4 amp foil getter 1940's
power triode DHT for last stage audio amplifier old production made in USA
one tube = 1 piece 6b4g tested TV7 = 54 (reference good at 38)
tested also on tube tester Funke W19S Ia (mA) = 44mA (reference good at 25mA)
box 171