The CV1167 (NR43) is an output pentode based on the Mullard PM24A. The envelope has both the CV and older NR Types on the glass indicating that it dates to before 1941.
Side view showing the pentode section high in the envelope - long leads.
The pinch and the base of the electrodes can be seen through the coating in the glass. The filament and three wire grids can be picked out.
The top mica and tension springs that end in V shaped hooks to hold the filament wire.
Here the loop of filament and grid wire can be seen - distorted by the glass.
The classic envelope is 40 mm in diameter and, excluding the B5 base pins, is 93 mm tall.
