http://www.webervst.com/wwwboard/tubes/calcbias.htm


Bias Settings For Safe Plate Dissipation - Class AB 70%    Class A 90%
Explain This
Class   
Tube Type    
Plate Voltage    
      mA
Calculate Plate Dissipation based on Voltage and Current readings

Plate Voltage

Cathode current (milliamps)

Plate dissipation (Watts)