The 6BA6 is described by Brimar as a variable μ pentode for use at HF. Most probably as RF amplifiers in radio receivers.
The grids are visible through the gap in the anode. The suppressor grid is close wound allowing it to be used as a second control element if required.
The main electrodes are assembled on a jig and the leads emerging from the base are cut to length and bent to shape. The operator then spot welds the two parts together.
The thin glass tube envelope is 18 mm in diameter and excluding the B7G base pins, is 46 mm long.
References: Data-sheet & 1040. Type 6BA6 was first introduced in 1950. See also1950 adverts.
