![](https://coimages.sciencemuseumgroup.org.uk/63/852/large_thumbnail_1946_0107.jpg)
McVitie Weston valve collection
- Made:
- circa 1924 in United States
- maker:
- Osram
![M-O AF amplifier valve, type D.E.4](https://coimages.sciencemuseumgroup.org.uk/453/600/medium_smg00262989.jpg)
M-O AF amplifier valve, type D.E.4., B4 base, marked Y650, pinch marked 4 (RMW/C32B - McVitie Weston number), by Osram, c. 1924.
M-O AF amplifier valve, type D.E.4., B4 base, marked Y650, pinch marked 4 (RMW/C32B - McVitie Weston number), by Osram, c. 1924.