The CV2729 (commercially the E80F) is a special quality pentode.
It was designed for audio amplifier use, normally in RC coupled designs. It is also specified for electrometer applications and the operating conditions are shown in the second set of parameters. In this application the input current to g1 is less than 0.1 nanoA.
The KB/PA identifies this valve as being made to specification K1001 or K1006, the B denotes qualification by a UK authority and the PA identifies the maker as Philips Teleindustri, Stockholm, Sweden.
The Philips name on the envelope. The control grid connection is shielded down to the glass base for maximum isolation.
The tops of the three wire grids.
The thin glass tube envelope is 20 mm diameter and excluding the B9A base pins stands 59 mm high.
Reference: Data-sheet. Type CV2729 was first introduced in 1951. See also1951 adverts.
