The KT63 was originally the N63, and was released in the IO based form in 1937. It is an audio output beam tetrode valve.

The anode load should be 7,000 Ω.

The remains of the Marconi label. The stylised lettering at the lower edge is MWT for Marconi's Wireless Telegraphy. An image of the full image can be seen here.

The view through the dome. The cathode tube is round, the control grid is wound on copper supports and has heat radiating fins on the tops of the supports. The suppressor supports are joined at the top. As a beam tetrode the suppressor mechanism will be beam plates not an open helical grid. Inside the screen grid wire can be seen against the white of the cathode oxide coating.

The classic envelope is 45 mm in diameter and, excluding the IO base pins, is 101 mm tall.

References: Data-sheet, ¹⁰⁴⁰ & ¹⁰⁴³. Type KT63 was first introduced in 1937. See also 1937 adverts.

Pin Connections

IO

1

2

3

4

5

6

7

8

m

h

a

g2

g1

nc

h

k