Virtual Valve Museum

Virtual Valve Museum

HomeFull List

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

STC CV2221 / V235A/1K Heil tube

Size This measures 65x19mm (42mm across the copper disk) and has a B7G base.


Heater voltage 6.3V
Heater current 0.3A
Nominal tuning range 7.5 to 11.5cm
Max dissipation anode plus resonator 15W
Anode voltage 150 to 420V
Resonator voltage 140 to 400V
Max screen voltage 400V
Max resonator dissipation 8W
Max cathode current 65mA
Max screen dissipation 1.5W

The anode should be 20V positive to the resonator when low noise output is required. The screen voltage must not exceed the resonator voltage by more than 50V. A permanent magnet of 1000 oersteds is required to focus the beam - 'Jessop' type 9501 and 10512 is recommended.

Pin Function
1 Grid 1
2 Cathode
3 Heater
4 Heater
5 Anode
6 Resonator
7 Grid 2

Probe Probe
The output probe can be seen here, encapsulated within the envelope.
Top quarter Bottom quarter