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EF54 / CV1136 / VR136 / 5A-156M signal amplifier pentode

EF54 size The valve measures 75x35mm overall and has a B9G base

The CV1136, or RL7, was a variant of the EF50. It had duplicate cathode leads and aligned grids to improve on the earlier design, to the extent that it was superior to acorn pentodes up to 300MHz.


Heater voltage 6.3V
Heater current 300mA
Max anode voltage 300V
Max screen voltage 300V
Max anode dissipation 3.0W
Max screen dissipation 1.7W
Mutual conductance 7.7mA/V
Anode impedance 500k ohms
Inner amplification factor 80.0
Max operating frequency 300MHz
Cag max 0.02pF
Cae max 5.3pF
Cge max 8.8pF
Cg1 g2 nom 2.1pF


Pin Function
1 Heater
2 Anode
3 Screen grid
4 Internal screen
5 Internal screen
6 Control grid
7 Internal screen
8 Internal screen
9 Heater
The cathode and suppressor grid are connected internally to the screen.

See also CV380.




VR136 5A/156M 5A/156M

VR136 version. Also an STC 5A/156M which shows Mullard EF54 on the rear.

5A/156M donated by Lionel Dray

This file was last modified 23:10:40, Wednesday February 23, 2022