The 6U8A is a triode pentode by designation but is constructed as a beam tetrode. The 6U8A differs from the 6U8 mainly in the fact that the heating time is tightly controlled.
The design purpose was in VHF radio and television between 80 MHz to 220 MHz. Bands II and III. The valve would be used as a mixer with the triode as local oscillator.
The 6U8A was used in many colour television chassis. The triode is medium μ and the pentode is a sharp cut-off type. The 6U8A can be used to replace 6GH8 or 6EA8.
The GE logo on the glass. The pentode (Beam tetrode) section on the left, screen in the centre and triode on the right.
The open end of the beam tetrode showing the bright beam forming plate and the screen grid support within.
The thin glass tube envelope is 21 mm in diameter, and excluding the B9A base pins is 47 mm tall.
