Virtual Valve Museum

Virtual Valve Museum
HomeFull List

This is an archive website. It will not receive any updates, additions or corrections.

NT39 / CV1222 / ACT6 Air Cooled Triode (ACT)

Size This valve measures 220mm x 50mm and has a 4-pin base.

This is an external anode triode designed to be air cooled.

Filament voltage 10V
Filament current 1.65A
Max anode voltage 1500V
Max anode dissipation 75W
Amplification factor 22
Mutual conductance 5.0mA/V
Anode impedance 4200 ohms
Max frequency for 75% anode rating 37MHz

 

Pin Function
1 n/c
2 Filament
3 Grid
4 Filament
TC Anode

Top view
Top view of the valve, above, and an internal view, below.
Inside view

 NT39
The NT39/CV1222 above has "No. 3880c 38X"
etched on the glass under the part number.
The ACT6 below carries the number 7120.

ACT6
Top quarter view Bottom quarter view