VR40
Triode · DHT · UX-4 · 1940
“Military PX25 variant.”
Power triode delivering 25W for push-pull and SET designs
Datasheet ↗SPICE
GAIN FACTOR0
PLATE IMPEDANCE0kΩ
TRANSCONDUCTANCE0mA/V
GAIN5%
POWER63%
DRIVE98%
LINEARITY95%
TYPICAL OPERATING POINT
EXECUTIVE SUMMARY
The VR40 is a directly-heated triode from Osram, introduced around 1940. It provides a gain factor (μ) of 5 with 2000Ω plate resistance. Commonly used in power applications. Military PX25 variant.
APPLICATIONS
SET outputPush-pull output
Generic triode power stage
• Hi-Fi stereo• Headphone amp
VS PX25
HISTORY
Introduced1940ManufacturerOsramEquivalentsPX25
Pre-WarSPECIFICATIONS
Heater Voltage4V
Heater Current2A
Max Plate Voltage400V
Max Power25W
Sensitivity2.5 mA/V
Gain Factor5
Internal Impedance2.0kΩ
PinoutUX-4
Era1940
RarityRare