Sensibly equivalent¶ to:
58 C1408 CV1900 VT-69
The 6D6 (=6U7 on IO base) 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).
The paper band around the top of the envelope is printed with the words - quality approved - special export test.
The construction is as a classic pentode. The three wire grids are helical and of different pitches. The suppressor is more open than the screen grid. The control grid will be wound with a variable pitch in order to generate the variable μ characteristic. Below the bottom mica the twisted and insulated heater wires can be seen entering the oxide coated cathode tube.
The classic envelope is 38 mm in diameter, and excluding the UX6 base pins is 107 mm tall.
References: Datasheet, 1040 & 1043. Type 6D6 was first introduced in 1936.
Absolute Maximum Operating Conditions¶
Updated February 13, 2013.