M-OV's first indirectly-heated HT rectifiers were the MU12 and MU14. These were in fact the same valve but only a minority of each production batch were good enough to withstand the full rating when tested. These few were labelled MU14.![](../pics/aau0015a.jpg)
The remains of the Osram paper label. The anode is ridged and has holes in it.![](../pics/aau0015b.jpg)
The anode full face.The classic envelope is 45 mm in diameter and excluding the B4 base pins, is 105 mm tall.References: Data-sheet & 1043. Type MU14 was first introduced in 1933. See also 1933 adverts. |