This is very good loadline calculator:
www.vtadiy.com
When you select the tube it loads default values from tube datasheet and appear a single ended. For push pull just pick pp-box. If you design cathode biased stage to get B+1 add V1=plate and g1=control grid voltages. When you add headroom there appear distortion values. Some tube datasheets have few different values. You can use calculator to test what others have designed when schematics have voltages and soon you get an idea what instrument amp loadlines look
Some tubes have grid lines up to g1=0V which means A1 and AB1 operation. Some tubes have grid lines which go to positive which means operation go to A2 and AB2 which typical 12ax7 does not necessarily do. Look "at g1=0" value which is output power what come when g1 drive signal go to 0V. Also when you drag cursor to grid lines there comes its voltage.
Universal Loadline Calculator
This calculator allows you to trace the anode characteristics graph, and to compute and tune loadline and operating point of various vacuum tubes.
www.vtadiy.com
When you select the tube it loads default values from tube datasheet and appear a single ended. For push pull just pick pp-box. If you design cathode biased stage to get B+1 add V1=plate and g1=control grid voltages. When you add headroom there appear distortion values. Some tube datasheets have few different values. You can use calculator to test what others have designed when schematics have voltages and soon you get an idea what instrument amp loadlines look
Some tubes have grid lines up to g1=0V which means A1 and AB1 operation. Some tubes have grid lines which go to positive which means operation go to A2 and AB2 which typical 12ax7 does not necessarily do. Look "at g1=0" value which is output power what come when g1 drive signal go to 0V. Also when you drag cursor to grid lines there comes its voltage.
