The CV4040 (commercially the S6F17) valve is a special quality version of the 6F17 miniature RF and pulse tetrode. The design is for pulse amplification.
The KB/F identifies this valve as being made to specification K1001 or K1006, the B denotes qualification by a UK authority and the F identifies the maker as STC, Paignton.
The reverse carries the STC name and Made in England together with the S6F17 designation. Note the screening of the anode lead down to the pin.
The control grid copper supports are topped off by a heat radiating fin. The beam plate can be seen as a shaped plate with a rectangular aperture.
The thin glass tube envelope is 18 mm in diameter and, excluding the B7G base pins, is 44 mm tall.
Reference: Data-sheet. Type CV4040 was first introduced in 1956. See also1956 adverts.
