The CV2523 is a double triode with special properties. The AC anode resistance is very low at 280 Ω and the mutual conductance is considerable at 7.5 mA/V. The suggested cathode bias resistor is given as 250 Ω.
This valve was used in power supplies as a series pass device. For hi-fi amplification the double triode could be used as a push-pull output stage.
The KB/Z identifies this valve as being made to specification K1001 or K1006, the B denotes qualification by a UK authority and the Z identifies the maker as MO Valve Company, Hammersmith.
The envelope is also marked with the commercial Type designation of 6AS7G and has the GEC logo that is the professional brand whereas Osram is the consumer brand.
Each anode is a pair of open rectangular boxes. The control grid can be seen to extend beyond the width of the anode.
Face view of one triode showing the grid winding passing flat across the cathode.
The classic envelope is 50 mm in diameter, and excluding the IO base pins, is 105 mm tall.
References: Data-sheet & 4040. Type CV2523 was first introduced in 1946. See also1946 adverts.