The 6AB8 is a triode plus output pentode primarily designed for use in television receivers (VHF 405 line models) with the triode as a frame blocking oscillator and the pentode as a frame output valve. Other applications include the use of the triode as a line blocking oscillator, AF voltage amplifier or in multivibrator circuits and the operation of the pentode as an audio output valve or a synchronising pulse separator.
The triode is mounted above the pentode and at right angles to it on the common cathode.
The connections rising past the pentode are not copper in this exhibit.
On the left is the rod connection to the triode anode. In the centre the connection to the triode grid is shielded by an open rectangular tray connected to the cathode and screen (pin 3). In other exhibits the tray is grey and not so clear.
The thin glass tube envelope is 20 mm in diameter and, excluding the B9A base pins, is 59 mm tall.
References: Data-sheet & 1040. Type 6AB8 was first introduced in 1950.