Sensibly equivalent¶ to:
9A1 A50M AC/VP1 CV3571 HP4106C VMP4G VP4A VPT4B
The MVS-Pen is a variable μ RF pentode designed for radio receivers. It is indirectly heated and features the then standard UK heater of 4.0 V at 1.0 A. Not all of the UK in the early 1930's had AC mains, some areas had DC mains and so radio sets had to have series heater chains. The DVS-Pen was the DC equivalent to the MVS-Pen.
Initially in 1933 the MVS-Pen came with a B5 base cap. In the same year the B7 base version was released.
The reverse is plain zinc paint.
The classic envelope is 45 mm in diameter, and excluding the B7 base pins is 105 mm tall.
References: Data-sheet, 1040 & 1043. Type MVS-Pen was first introduced in 1933. See also 1933 adverts.
Absolute Maximum Operating Conditions¶
Thanks to Andy Cowley for supplying the above PDF datasheet.
Updated June 04, 2023.