Task: Text Simplification
Input (English): tube sound -lrb- or valve sound -rrb- is the characteristic sound associated with a vacuum tube-based audio amplifier.
Output (English): tube sound -lrb- or valve sound -rrb- is the typical sound related with a vacuum tube-based audio amplifier -lrb- an electronic device for increasing the amplitude of electrical signals , used chiefly in sound reproduction -rrb-.