Single-plate 2A3 variant on Octal base — similar application but verify electrical compatibility
Electrical Specifications
Absolute Maximum
Anode Dissipation (max)Max. Plate Dissipation15W
Max Grid ResistorMax. Grid Resistor (fixed bias)0.05MΩ
Max Grid ResistorMax. Grid Resistor (self bias)0.5MΩ
Typical Operating
Anode Voltage (typical)Plate Voltage (max, Class A1)250V
Notes
The 6B4G is the Octal-base version of the 2A3 with a 6.3V coated filament instead of the 2A3's 2.5V thoriated tungsten filament. This makes it more practical for standard 6.3V heater supplies.
Class A1 single-ended: 3.2W output at 250V plate, -45V grid, 60mA, into 2500Ω load with 5% second harmonic distortion.
Class AB1 push-pull (two tubes): 15W output at 325V plate, fixed bias -68V, into 3000Ω effective plate-to-plate load with 2.5% THD.
Grid circuit resistance max: 0.05 MΩ with fixed bias, 0.5 MΩ with self (cathode) bias.
The 6S4S (6С4С) is the Soviet equivalent with the same Octal base and 6.3V filament.
Brans Vademecum lists the 2A3, 2A3W, 6A3, AC042, and ZA3W as equivalents in the power triode Class B table (IIIb).
Pin Layout — Octal
1No Connection
2Filament
3Plate
4
Socket-Compatible Tubes ⚠ Not electrically compatible