题目选项分析

Although they are more temperamental and far more expensive than transistor-driven amplifiers, vacuum-tube-driven amplifiers are preferred by many audiophiles and audio professionals because these amplifiers produce warmer, richer tones.

Although they are more temperamental and far more expensive than transistor-driven amplifiers, vacuum-tube-driven amplifiers are preferred because they produce warmer, richer tones by many audiophiles and audio professionals.