user: Question: Name the # tubes with Det/Pre-amp of X and audio amp of X X (push-pull)
Columns: ['# Tubes', 'Converter', 'Det/Pre-amp', 'Audio Amp', 'Rectifier']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['4', 'X', 'X', 'X', 'X']
SQL:

assistant: SELECT "# Tubes" FROM "Table" WHERE "Det/Pre-amp" = 'X' AND "Audio Amp" = 'X X (push-pull)';