The distortion produced by your audio amplifier may be louder than the noise produced by a major appliance!
John Siau took Stereophile's THD+N measurements for 7 of their top-rated power amplifiers and replotted the data in terms of sound pressure level at the listening position. Once percent is converted to dB relative to our threshold of hearing, the test results become meaningful, and somewhat shocking.
John shows exactly how much noise each amplifier produces, and he shows exactly how loud the distortion is at every playback level. All of this information is hidden within traditional THD+N vs. power plots. The meaning is obscured by the traditional percent and power units. These traditional units have no direct relationship to the real world. John converts these units and the data comes alive!
John shows that the noise and distortion is well above the threshold of normal hearing, even when selecting some of the very best audio amplifiers. One of the seven amplifiers is radically different. It is the only amplifier out of this elite group that produces absolutely no audible noise or distortion.
