The X79 is a triode hexode frequency changer or mixer. The triode control grid is connected internally to the oscillator injection grid (g3) of the hexode.

The Osram brand label of the M-OV company.

The thin glass tube envelope is 21 mm in diameter, and excluding the B9A base pins is 48 mm tall.

References: Data-sheet & ¹⁰⁴⁰. Type X79 was first introduced in 1950. See also 1950 adverts.

Pin Connections

B9A

1

2

3

4

5

6

7

8

9

g2,g4

g1

k

h

h

a(h)

g1(t),g3

a(t)

ic