Bench tool
This is the live tubes.csv data (not the curated substitution guide). For drop-in vs rebias advice see Tube Substitution / Cross-Reference.
Offline power-tube reference
Searchable offline power-tube database: max dissipation, pinouts, filament, plate/screen ranges from the DiMastro GTA tubes.csv.
Bench tool
This is the live tubes.csv data (not the curated substitution guide). For drop-in vs rebias advice see Tube Substitution / Cross-Reference.