The ECF82 is a high slope triode beam tetrode designed for television use as a frequency changer or mixer. It was also found to be effective as an audio phase splitter.
Made in England. Plus STC were members of the BVA.
The pentode is actually a beam tetrode.
Both the triode and the beam tetrode have control grids wound on copper supports.
The thin glass tube envelope is 20 mm in diameter, and excluding the B9A base pins is 48 mm tall.
References: Data-sheet & 1040 Type ECF82 was first introduced in 1953. See also1953 adverts.
