The VR65A is an amplifier pentode with external zinc loaded paint metallisation as shielding. The 4.0 V heater was common in the 1930s when mains sets first began to appear.
By the 1960s they were again in limited demand for maintaining ex-Services test equipment (oscilloscopes, etc.) which was then popular in Amateur circles, and in Third-World countries.
When unwrapped all of the zinc loaded paint fell away and so we have a chance to see how it was constructed.
This and the main image show a flat rectangular oxide coated cathode with a small front to back dimension when compared to the width. Three wire grids are present for a true pentode. The anode is a pair of small flat plates placed either side of the cathode flat front.
Above the pinch is screening below the lower mica.
The cathode top can be seen through the top mica. Although the gettering obscures most of the detail the wire grids and anode plate can be identified.
The classic envelope is 30 mm in diameter and, excluding the MO base pins, is 82 mm tall.
References: Private communication, data-sheet, 1040 & 1043. Type VR65A was first introduced in 1938. See also1938 adverts.
