The EF86 is the standard early stage audio pre-amplifier valve. This exhibit was made by Mullard who designed the EF86. It was first used in their 5-10 amplifier from 1954. This particular valve was made by Philips (the Mullard parent company) in Holland.The EF86 was developed from the B8A EF40.Mullard describe the EF86 as a low noise pentode intended for use as a RC coupled AF voltage amplifier, particularly in the early stages of high gain audio amplifiers, microphone pre-amplifiers and magnetic tape recorders.![](../pics/aaq0204a.jpg)
The screening mesh and below the bottom mica addditional screening.The thin glass tube envelope is 20 mm in diameter and, excluding the B9A base pins, is 48 mm tall.Reference: Data-sheet & 1040. Type EF86 was first introduced in 1953. See also 1953 adverts. |