The 6BZ7 is a double amplifier triode designed for cascode operation is VHF television tuners. The standard European valve for this task was the PCC84. The 4BZ7 was electrically the same but the heater rating was 600 mA at 4.2 Volts for series heater chains.
The orange lettering.
Made in USA on the glass and the twin triode section within. The bright electrostatic screen separates the triodes. The control grids can be seen through the holes in the ends of the box anodes.
The thin glass tube envelope is 21 mm in diameter and, excluding the B9A base pins, is 48 mm tall.
Reference: Data-sheet. Type 6BZ7 was first introduced in 1956. See also1956 adverts.
