Sensibly equivalent¶ to:
The 15D1 is a heptode frequency changer for use in both AC and Universal sets. Brimar describe the operation of the valve as being a triode oscillator and a vari-μ tetrode, however, the construction is as a heptode.
The 15A2 differs only in the fact that the heater rating is 4.0 Volts at 0.65 Amp.
Thanks to Mike Edwards for sending these images.
The heptode construction. The oscillator anode can be seen as two plain vertical rods. The anode shape is oval.
The classic envelope is 38 mm in diameter, and excluding the B7 base pins is 97 mm tall.
References: Data-sheet, 1040 & 1043. Type 15D1 was first introduced in 1934. See also 1934 adverts.
Absolute Maximum Operating Conditions¶
Updated December21, 2020.