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The CV2465 (commercially the 5B/254G a 5B/254M with flying leads) miniature beam tetrode was designed to have the same ratings as the classic 807. The difference in size between the 807 and this valve shows the extent to which valve technology matured during WWII and the effect of the introduction of the pressed glass base. This particular base was the earliest to be developed with eight equi-spaced pins and an external metal collar to hide the envelope seal and provide a locating spigot.

Electrically the valve is also very similar to the STC 5B/251M and electrically identical to the 5B/255M. The latter has the anode connected at the base and one less connection to the cathode.

The KB/FE identifies this valve as being made to specification K1001 or K1006, the B denotes qualification by a UK authority and the FE identifies the maker as STC, Oldway (Additional to Paignton factory 'F').

The anode has an added flange in the centre of the heat generating face - opposite the cathode. At the base is the efficient screening that the 807 employed and the two wire grids and the bright beam plate can be seen.

The wide glass tube envelope is 29 mm in diameter and, excluding the B8B base pins, is 85 mm tall.

References: Data-sheet & ¹⁰⁴⁰. Type CV2465 was first introduced in 1958. See also 1958 adverts.

Pin Connections

Absolute Maximum Operating Conditions^¶

Thanks to Frank Philipse for supplying the above PDF datasheet.