The VT-69 is the American purchase specification for the commercial 6D6. The valve is a variable μ pentode for AGC controlled amplifiers at RF and IF in superhet radio receivers.
Electrically the 6D6 (UX6 base) is identical to the Type 58 (UX6 base) and the 6U7G.
The Ken-Rad name. On the glass can just be seen the etched 6D6 in an octagon outline.
The SC961A appears on several exhibits.
The top view reveals the pentode construction. The control grid is wound on copper supports and connects to the top cap.
The classic envelope is 38 mm in diameter, and excluding the UX6 base pins is 103 mm tall.
References: Data-sheet, 1040 & 1043. Type VT-69 was first introduced in 1936. See also1936 adverts.
