The RV120/350 was designed to work with a maximum reservoir capacitor of 32 µF and to have an effective series resistance of 100 Ohms. The RV120/350S was the same valve but fitted with a Ct8 side contact base cap.
The twin anodes are folded and stitched together. Unlike RV120/350 the anode plates are smooth and not ribbed. Also the filament ribbon is tensioned with a spring that is omitted in the other example.
The filament tension springs.
A closer view.
The ribbon filament is oxide coated and spot welded to the supports.
The classic envelope is 45 mm in diameter and, excluding the B4 base pins, is 100 mm tall.
References: Data-sheet & 1043. Type RV120/350 was first introduced in 1938. See also1938 adverts.
