2A3-40 JJ
Triode · DHT · UX-4 · 2005
“Enhanced 2A3.”
High-power directly-heated triode for single-ended amplification
Datasheet ↗SPICE
GAIN FACTOR0
PLATE IMPEDANCE0Ω
TRANSCONDUCTANCE0mA/V
GAIN4%
POWER100%
DRIVE99%
LINEARITY95%
TYPICAL OPERATING POINT
EXECUTIVE SUMMARY
The 2A3-40 JJ is a directly-heated triode from JJ Electronic, introduced around 2005. It provides a gain factor (μ) of 4.2 with 760Ω plate resistance. Commonly used in power (set) applications. Enhanced 2A3.
APPLICATIONS
SET outputPush-pull outputHeadphone output
Generic triode power (set) stage
• Hi-Fi stereo• Headphone amp• PA/public address
VS 2A3
HISTORY
Introduced2005ManufacturerJJ ElectronicEquivalents2A3
ModernSPECIFICATIONS
Heater Voltage2.5V
Heater Current2.5A
Max Plate Voltage450V
Max Power40W
Sensitivity5.5 mA/V
Gain Factor4.2
Internal Impedance760Ω
PinoutUX-4
Era2005
RarityCommon