The VR65A is a television HF amplifier pentode for operation at 45 MHz with external metallisation as shielding. The original design was from Mazda, and other manufacturers copied this successful design after it had become established.This exhibit is in a tubular envelope, the other VR65A exhibit is in a classic envelope of the same design as the branded SP41 and SP61, thereby suggesting its origin.By contrast with the short lived EF50, the SP41, SP61 and the VR65A were virtually indestructible.The 4.0 V heater was common in the UK during the 1930s when mains sets first began to appear. The first American AC heater standard was 2.5 Volts. The mid 1930's American 6.3 Volt standard was eventually universally adopted.The wide glass tube envelope is 30 mm in diameter and, excluding the MO base pins, is 80 mm tall.References: Data-sheet, 1040 & 1043. Type VR65A was first introduced in 1938. See also 1938 adverts. |
