TJ FULLMUSIC 300B+ Data Sheet

Classification: Dome-type bulb of glass, a white ceramic base with four-prong bayonet golden pins, oxide coated filamentary, carbon plate triode.

Application: Audio frequency amplifier where power outputs of approximately 22.5watts or less is required at relatively low plate voltages.

Dimensions: Dimensions, outline diagrams of the tube and bases, and the arrangement of electrode connections to the base terminals are shown in Figures 1, 2.

Nominal operating conditions and parameters:

Filament voltage* ………………………………………………..5V

Nominal filament current ……………………………………2.4A

Plate voltage ………………………………………………………..400V

Grid voltage** ……………………………………………………..-70V

Plate current ……………………………………………………….120mA

Amplification factor …………………………………………….3.85

Grid to plate transconductance ………………………….8.5mA / V 

Grid current …………………………………………………………0.05 μ A

Plate resistance …………………………………………………..450 ohms

Load resistance …………………………………………………..2.0 kohms

*Alternating-current filament supply or Direct-current filament supply.

**Alternating-current filament supply is used. The grid and plate returns should be connected to a center tap on the secondary of the filament transformer. Direct-current filament supply is used. The grid and platter returns are connected to the negative end of the filament. Characteristics-Average characteristics on Figure 3 shows typical curves of plate currents of grid voltage for several values of plate voltages. It is alternating-current filament supply.