NAD 10 20 B Infrasonic Filtering, Musically Useful Tone Controls, Digital-Ready Dynamic Range

Infrasonic Filtering

In a laboratory, response down to DC and up to frequencies in the megahertz range may be ideal, but in real-world environments the musical signal often is contaminated by interference at frequencies below and above the audible range: turntable rumble, floor vibration, tonearm/stylus resonance, radio interference. Such extraneous signals can impair an amplifier’s handling of musical sound, waste amplifier power and woofer cone excursion, and contribute to audible intermodulation distortion in loud-speakers.

The precise, minimum-phase, audio bandpass filtering in the NAD 1020B strips off such interference while preserving accurate response at audible frequencies, ensuring the cleanest possible amplification of the musical signal.

Musically Useful Tone Controls

Among some pre-amp designers it has become fashionable to omit tone controls. But tone controls are a genuinely helpful aid to enjoyable music listening, as long as they are correctly designed-meaning that they must not add audible distortion or noise, and must not alter the basic tonal balance in the critical midrange. In the NAD 1020B the Bass and Treble controls have been designed so that, at moderate boost/cut settings, they provide musically useful corrections at very low and high frequencies while the midrange from 300 to 1500 Hz remains essentially flat. Since high circuit impedances often add a subtle veil of noise to reproduced sound, the 1020B employs a high- current tone control amplifier stage with low impedances throughout.

Digital-Ready Dynamic Range

To use a pure-digital disc player, just connect its line-level outputs to the 1020B’s AUX inputs, and play. The 1020B’s AUX and TAPE inputs cannot be overloaded by high-level signal peaks, and the 1020B’s signal to noise ratio exceeds that of the widest-range digital recording systems.

High Current Output Buffer

In addition to its conventional pre-amp outputs the 1020B has a high-current output stage (a miniature power amplifier circuit) that can produce output signals of up to 15 volts with low output impedance.

These signals are fed both to the front-panel headphones jack and to an extra set of “high level” pre-amp output jacks on the rear panel. With this circuit the 1020B can drive virtually all non-electrostatic headphones, even low- sensitivity models, to full output. And with its low 150-ohm output impedance it can easily drive several power amplifiers in parallel, drive professional 600-ohm studio equipment, or drive the long connecting cables required for active powered loud-speakers or for remotely located power amplifiers.

Designed for Value

NAD stereo components have been praised around the world for their unusual combination of modest price, uncomplicated controls, advanced engineering, and state-of-the-art sonic performance. The NAD 1020B preamplifier is squarely in that tradition. For accuracy, for freedom from noise and distortion, for transparent and supremely musical sound quality, the 1020B is unmatched in value.