NAD is an electronics firm whose products include low-cost home audiophile amplifiers and related components. NAD was an acronym for New Acoustic Dimension. The company was founded in London, England in 1972 by Dr. Martin L. Borish, an electrical engineer with a Ph.D. in Physics. Its most famous product is the late-1970s NAD 3020 amplifier, designed by Bjørn Erik Edvardsen, which became a staple of low-budget Hi-Fi in Britain. NAD’s philosophy is to include only genuinely useful features for aesthetically understated designs. The company focuses on ‘effective power’ and its amplifiers have been known for delivering generous headroom, meaning that they can deliver dynamic power bursts far in excess of their rated power. The key to this feature is a flexible power supply which stores significant reserve current for quick release at moments of high musical load. The various incarnations of this design have been associated with different names over the years including Power Envelope and recently PowerDrive.
Additional benefits of this approach include the fact that amplifiers using this technology can handle complex, real-life, lower-impedance loudspeaker loads as compared with the simple 8-ohm resistor typically used to calculate advertised power ratings and the fact that the circuitry in this approach requires less cooling, while maintaining ability to handle complex impedance loads as low as 2 ohms. An amplifier that is overdriven, or pushed beyond its designed power capabilities, produces audible distortion known as clipping by cutting off extremes of the music waveform, resulting in harshly unpleasant sound and threatening damage to speakers, particularly tweeters. NAD amplifiers incorporate a user-defeatable ‘Soft-Clipping’ circuit to address this issue. It gently transforms the music waveform as the point of clipping approaches, the goal being clearer reproduction and simultaneous protection of speakers.
The Daily Omnivore 
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