Sensibly equivalent¶ to:
Type 6BN6 is a late 1940s 'gated beam' FM discriminator.
The envelope appears to contain two or three electrode systems, but close examination reveals that there is only one heater/cathode assembly, seen on the left. The ribbon of electrons that are formed (the beam) is guided across the width of the valve to the cavity (anode) on the right of the picture.
Thanks to Brian Cuff for the following information on the 6BN6. I remember this valve being used in the first Ampex video tape recorders the VR1000A. They were used in the demodulators which demodded the video carrier from tape. It was referred to as a gated beam valve and the FM demodulator circuit contained only 1 tuned circuit (a quadrature coil). At the time, in the very early 1960s, circuit designs existed for the use of the 6BN6 for the reception of FM Band II Radio broadcasts and the solution worked well, however, this was too expensive a solution for manufacturers to adopt for general consumer products.
The first part of the data-sheet is on entry 6BN6.
The thin glass tube envelope is 17 mm in diameter and, excluding the B7G base pins, is 57 mm tall.
References: Data-sheet & Brian Cuff. Type 6BN6 was first introduced in 1965.
Absolute Maximum Operating Conditions¶
PDF scanned from an original document held by the museum
Updated November 28, 2020. shape:thin.glass.tube construction:all.glass type:pentode age:1940.1950 base:b7g heater:6.3v pins:7 pin:1.k pin:2.g1 pin:3.h pin:4.h pin:5.g2 pin:6.g3 pin:7.a