AUDIO VALVES: MHL4 154V 164V 41MLF CV1038 CV3547 NR26 VR38 TRIODE

The MHL4 amplifier triode (mu = 20) was not much used in domestic radios because the MH4 (mu = 40) was better suited to the detector/first AF task. However, the MHL4 did see service in professional and military applications over many years until it was superseded by the  Octal based L63 which shows similar characteristics.

The MHL4 was first intorduced by Osram  in 1929. 

MHL4 

MHL4 

MHL4