Tube Bias Calculator

Calculate Tube Bias ; Select tube ---------- 6J7 0.75W 6SL7GT 1W 6SL7 1.1W 12AX7 2W 12AY7 3W 12AT7 5W 12AU7 5.5W 12BH7 7W 12BH7A 7W 6SN7 7.5W 6CL6 7.5W 6K6GT 8.5W ECC99 10W SV83 12W EL84 12W 5673 12W 5AQ5 12W 6AQ5 12W 6BQ5 12W 6CM6 12W 7189 12W 12AQ5 12W 12AB5 12W 6V6 12W 6V6GT 12W 6V6GTA 12W 300B 40W JJ6V6S 14W 2A3 15W 7591 15W 6N3C 20W 6N3C-E 20.5W 6P3S 20W 6P3S-E 20.5W 5881 23W 6CA7 25W 6CA7 25W EL34 25W EL34LS 22W KT66 25W KT77 25W 5881WXT 26W 6L6 19W 6L6G 19W 6L6GB 19W 6L6WGB 26W 6L6WGC 26W 6L6GC 30W 6L6WXT 30W 7027 35W 7027A 35W 300B 36W KT88 35W KT88S 42W 6550 42W 6550A 42W 6550C 35W KT90 50W KT120 60W KT150 70W Plate to Cathode Voltage :  VDC (plate voltage minus cathode voltage) Tube Max Dissipation = watts  100% Pa Class A Fixed Bias 70% Cool = mA Watts 80% Average = mA Watts 90% Max Safe Dissipation = mA Watts Class AB Fixed Bias 50% Cool = mA Watts 60% Average = mA Watts 70% Max Safe Dissipation = mA Watts Cathode Bias 85% Cool = mA Watts 95% Average = mA Watts 100% Max Safe Dissipation = mA Watts Fixed bias amps have a bias circuit that puts a negative voltage on the power tube grid. The grid of cathode biased amps will be at 0 volts. Tube Dissipation Using Cathode Resistor Voltage Drop Select tube ---------- 2A3 15W 6J7 0.75W 6SL7GT 1W 6SL7 1.1W 12AX7 2W 12AY7 3W 12AT7 5W 12AU7 5.5W 12BH7 7W 12BH7A 7W 6SN7 7.5W 6CL6 7.5W 6K6GT 8.5W ECC99 10W SV83 12W EL84 12W 5673 12W 5AQ5 12W 6AQ5 12W 6BQ5 12W 6CM6 12W 7189 12W 12AQ5 12W 12AB5 12W 6V6 12W 6V6GT 12W 6V6GTA 12W 300B 40W JJ6V6S 14W 7591 15W 6N3C 20W 6N3C-E 20.5W 6P3S 20W 6P3S-E 20.5W 5881 23W 6CA7 25W 6CA7 25W EL34 25W EL34LS 22W KT66 25W KT77 25W 5881WXT 26W 6L6 19W 6L6G 19W 6L6GB 19W 6L6WGB 26W 6L6WGC 26W 6L6GC 30W 6L6WXT 30W 7027 35W 7027A 35W 300B 36W KT88 35W KT88S 42W 6550 42W 6550A 42W 6550C 35W KT90 50W KT120 60W KT150 70W Plate to Cathode Voltage : VDC (plate voltage minus cathode voltage) Number of Tubes that share a cathode resistor : Enter Voltage Across Cathode Resistor : VDC Enter Cathode Resistor : Ohm Total Cathode Current = mA Total Plate Current = mA  = Cathode current minus approx. screen current of 5.5% Plate Current per Tube = mA  = Total Plate Current / Number of Tubes Plate Dissipation per Tube = W  = Plate Current per Tube x Plate Voltage Plate Dissipation per Tube % =  % If your tube is a triode (or dual triode with both triodes used) your plate current is mA Plate Dissipation is  Watt  =  % Calculate Tube Dissipation Using Plate Current Select the tube you want to calculate ---------- 6J7 0.75W 6SL7GT 1W 6SL7 1.1W 12AX7 2W 12AY7 3W 12AT7 5W 12AU7 5.5W 12BH7 7W 12BH7A 7W 6SN7 7.5W 6CL6 7.5W 6K6GT 8.5W ECC99 10W SV83 12W EL84 12W 5673 12W 5AQ5 12W 6AQ5 12W 6BQ5 12W 6CM6 12W 7189 12W 12AQ5 12W 12AB5 12W 6V6 12W 6V6GT 12W 6V6GTA 12W JJ6V6S 14W 2A3 15W 7591 15W 6N3C 20W 6N3C-E 20.5W 6P3S 20W 6P3S-E 20.5W 5881 23W 6CA7 25W 6CA7 25W EL34 25W EL34LS 22W KT66 25W KT77 25W 5881WXT 26W 6L6 19W 6L6G 19W 6L6GB 19W 6L6WGB 26W 6L6WGC 26W 6L6GC 30W 6L6WXT 30W 7027 35W 7027A 35W 300B 36W KT88 35W KT88S 42W 6550 42W 6550A 42W 6550C 35W KT90 50W KT120 60W KT150 70W Plate Voltage : VDC (plate voltage minus cathode voltage) Plate Current : mA Plate Dissipation = watts Plate Dissipation = % <<< Back