The Z77 from M-OV was another designation for the ubiquitous EF91 of the late 1940s and here it carries the professional GEC label.
The GEC brand label. Above the top mica is a screen and also heat dissipating fins on the control grid supports.The thin glass tube envelope is 18 mm in diameter and, excluding the B7G base pins, is 46 mm tall.References: Data-sheet & 1040 Type Z77 was first introduced in 1947. See also 1947 adverts. |
