The 6DQ6A is a television line output valve designed for sets with a parallel heater supply. The 12DQ6A and 17DQ6A differ only in heater rating and both are designed for series heater chains and have controlled warm-up characteristics.
The rating given below are for typical applications. In line output service peak anode voltages can rise to 6,000 Volts but an absolute value of DC would be 700 Volts. The anode is rated at 15 Watts dissipation.
The RCA identification. The ends of the anode are open.
Looking across the anode showing the ends of the grids. The working faces of the anode are to the left and right. The thin cooling fins attach to the centre of the the anode working faces. The two inner grids have the wires shaped so as to pass flat across the cathode. The grid wires are aligned so that the screen lies in the same plane as the control grid.
The octal base shell conceals the glass foot base and thus this is essentially an all glass valve on an octal base.
The top mica showing the copper supports for the control grid.
The wide glass tube envelope is 36 mm in diameter, and excluding the IO base pins is 87 mm tall.
Reference: Data-sheet. Type 6DQ6A was first introduced in 1956.