Bias Calculator Bias Settings For Safe Plate Dissipation Class AB: 70% Class A: 90% Class AB A Tube Type EL84 6K6GT 6V6 6V6GTA 6L6 6L6GC 6L6WGB 5881 EL34 5763 7189 7591 KT66 KT88 7027 6CA7 6BQ5 Plate Voltage mA CALCULATE PLATE DISSIPATIONBased on Plate Voltage and Cathode Current Readings In these calculations, 5% of the cathode current is assumed to be screen current. This calculator is for a single tube. Plate voltageDC voltage measured between plate and cathode. (Actual Plate Voltage)Example:Octal – pins 3 and 89 pin – pins 7 and 3 Cathode Current (milliamps)Displays Approximate Plate Current After Calculation Plate Dissipation (Watts) Note: For calculating plate dissipation in cathode biased circuits, subtract the measured cathode voltage from the measured plate voltage and use that as the plate voltage in the calculator above. CALCULATE PLATE DISSIPATION (In Cathode Biased Output Stage)Based on Voltage and Resistance Readings In these calculations, 5% of the cathode current is assumed to be screen current. With multiple tubes sharing the same cathode resistor, this calculator assumes the tubes are fairly well matched. How many tubes share the same cathode resistor? (typically 1 to 4) Voltage measured across cathode resistor Actual resistance of cathode resistor DC voltage measured between plate and cathode. (Actual Plate Voltage)Example:Octal – pins 3 and 89 pin – pins 7 and 3 Plate dissipation per tube (Watts) Approximate plate current in each tube (in milliamps) Will calculate and display plate power dissipation and approximate plate current per tube.