<< Product 211 Vacuum Tube



Classification-column-type bulb of glass, copper-ceramic base with four gold pins, oxide coated filamentary, carbon plate triode.
Application-Audio power amplifier Class A or Class B or Class C .
Dimensions-Dimensions, outline diagrams of the tube and bases, and the arrangement of electrode connections to the base terminals are shown in Figures 1, and 2.

Nominal operating conditions and parameters

Filament voltage”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­10V
Nominal filament current”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­0.6 A
Plate voltage”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­1250 V
Grid voltage”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­£­70 V
Plate current”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­100 mA
Amplification factor”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­12
Load resistance”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­7 kohms
Output power”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­”­10W

Suggest operating conditions and parameters
Class A power amplifier of single tube

Plate voltage 750 1000 1250 V
Grid voltage -46 -61 -80 V
Load resistance 8.8 7.6 9.2 kohms
Plate current 34 53 60 mA
Signal voltage(pk) 41 56 75 V
Plate resistance 4.4 3.8 3.6 kohms
Output power 5.6 12 19.7 W

Class B power amplifier of push-pull

Plate voltage 1000 1250 V
Grid voltage -72 -95 V
Load resistance 6.9 9 kohms
Plate current(0 single) 20 20 mA
Plate current(max.single) 320 320 mA
Signal voltage(pk) 380 410 V
Output power 200 260 W

Class B power amplifier of single tube(modulate coefficient shall be 1)

Plate voltage 1000 1250 V
Grid voltage -72 -95 V
Plate current 130 106 mA
Signal voltage(pk) 125 125 V
Output powe 40 42 W
Grid current(approx) 5 1 mA
Grid power(input)(approx) 10 7.5 W

Class C power amplifier of single tube(max. modulate coefficient shall be 1)

Plate voltage 750 1000 V
Grid voltage -200 -260 V
Plate current 150 150 mA
Signal voltage(pk) 350 410 V
Output powe”­”­”­”­ 65 100 W
Grid current(approx)”­”­”­ 35 35 mA
Grid power(input)(approx) 12 14 W


Figure 3 . shown typical curves of plate currents of grid voltage for several values of plate voltages. It is alternating-current filament supply.


Limiting Operation Conditions for Safe Nor-nor simultaneous ratings

  Class Apush-pull Class B Class B Class C  
Maximum plate voltage 1250 1250 1250 1000 volts
Maximum plate dissipation 75 100 100 67 watts
Maximum plate current(max. sig per tube)   175 150 175 mA
Maximum Grid current       50 mA