This exhibit is a full wave rectifier of a type supplied to the UK armed forces before the CV system was introduced in 1941. When the CV system became operational the VU39A was re-classified as the CV1569.
The performance is close to that of the Mazda UU5.
Construction is as an indirectly heated rectifier, however, the heaters are run in parallel with the cathodes tied to one side of the heater. One cathode strap can be seen at the lower right.
The anodes connect at the top to vertical rods that pass the length of the valve.
The classic envelope is 44 mm in diameter and excluding the B4 base pins, is 100 mm tall.
