The CV1366 is a screened transmitting pentode with the V248A as the prototype. The old Army service code is ATP4. The anode dissipation is 5 Watts.
No maker is indicated but the MO base was used only by Mazda.
The Toran box has the Type designation written in felt tip pen and this suggests that Toran were a reseller.
The KB/B identifies this valve as being made to specification K1001 or K1006, the B denotes qualification by a UK authority and the B identifies the maker as Edison Swan, Baldock, pre Sept 1945.
The valve has two sections connected internally in parallel.
One pentode section with filament tensions springs above.
The top mica hold the filament springs and the mica disc below has the fingers that grip the inside of the glass bulb. The tops of the grid supports can be seen.
A closer view. The helical springs have a hook in the centre.
The classic envelope is 39 mm in diameter, and excluding the MO base pins is 97 mm tall.
Reference: Data-sheet. Type CV1366 was first introduced in 1940. See also1940 adverts.
