Sensibly equivalent¶ to:
The ECC81 was designed for RF voltage amplifier use. The exhibit is labeled Clairtone and Great Britain. The mark made by the machinery that closed off the glass tube is a match for the Mullard ECC81.
Side on the triode section can be seen to be nearly flat.
The thin glass tube envelope is 20 mm in diameter and excluding B9A base pins the length is 49 mm.
References: Data-sheet & 1040.
Absolute Maximum Operating Conditions¶
Updated March 31, 2017. shape:thin.glass.tube construction:all.glass type:double.triode age:1950.1960 base:b9a heater:6.3v pins:9 pin:1.a pin:2.g1 pin:3.k pin:4.h pin:5.h pin:6.a pin:7.g1 pin:8.k pin:9.hct