6SL7is high amplifier triode tube Uh---------------------6.3 V Ih----------------------0.3 A Maximum Rating Anode Voltage--------------300 V Positive Grid--------------0 -- V Anode Disspation--------1 W Max Cathode current-------120 mA Heater Filament Voltage------±90 V Typical Operating Conditions Class A1 Amplifier Ua-----------250 v -Ug----------2 --- v Ia-----------2.3 mA Gm-----------1.6 mA/V ri-----------44 kΩ µ -----------------70 Single tube A1 Amplifier Ua----------300 500 v Ug2---------250 200 v Rk-------- 140 280 Ω Ia----------83 50 mA Ig2---------8 1.6 mA Ri----------24 39 kΩ Gm----------6.5 5.7 mA/V RL----------3 6 kΩ Pout--------6.4 11.5 W Dtot--------6 12 %