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VR40

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equivalents
CV1040 - DO24 - NR47 - PX25
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HMS Collingwood Museum
The VR40 is the PX25 (PP5/400) in military uniform.
This early audio power triode was one of the first to give a significant output. 26 Watts to the loudspeakers of the time was suitable to fill a small hall. With transformers of the period being less efficient than later designs an audio power amplifier using a pair of these valves was a substantial piece of equipment, and heavy.
The ratings given are for class AB1 push pull for a pair of such valves. Under these conditions the grids would require 108 Volts peak to peak to achieve full output.
The balloon envelope has a maximum diameter of 60 mm and excluding the B4 base pins it is 133 mm tall.
 
Pin Connections
B4
1
2
3
4
a
g
f
f
 
Absolute Maximum Operating Conditions
Triode
Vh
Ah
Va
Vg
mAa
Pout
D
4.0
2.0
500
-54
82
26
4%

This exhibit was last updated on 02 March 2005