4020A AM/FM Tuner

Date of manufacture : ? - Jan 81

Please note that this document contains the text from the original product brochure, and some technical statements may now be out of date

The NAD 4020A is a rationally-engineered, moderately- priced AM/FM tuner, whose performance in most locations and with most broadcasts is audibly identical to that of many more expensive and elaborate tuners. The 4020’s quality of sound is limited only by the quality of the transmitted broadcast.

Recent dramatic advances in FM tuner circuitry, particularly in the development of inexpensive but high- performance “building block” circuit modules, have been incorporated in the 4020A to provide excellent sound at a reasonable price.

Such crucial design parameters as sensitivity, low distortion and wide stereo separation have been given priority over the inclusion of costly superfluous features and esoteric circuitry whose benefits are totally inaudible except in extreme reception conditions. But no compromises whatsoever have been made in those performance areas which relate directly to the 4020’s listening quality in normal (and even somewhat difficult) reception locations.

HIGH SENSITIVITY

The “front end” tuning circuit, for example, employs a Junction FET amplifier, for an optimum combination of sensitivity to weak signals and resistance to cross-- modulation from strong signals. The intermediate frequency (I.F.) amplifier, a high-gain IC, provides excellent limiting (static suppression), very good AM rejection (suppression of multipath interference), and smooth muting of interstation noise. LOW DISTORTION While budget-priced tuners commonly contain one or two ceramic I.F. filters, the NAD 4020A employs a total of three. Their sharp selectivity minimises interference from adjacent stations on the increasingly crowded FM dial, and their linear-phase response contributes to minimum distortion of stereo broadcasts. Multiplex stereo decoding is performed by the latest phase-locked loop (PLL) IC. In addition to low noise and wide stereo separation, the PLL decoder yields the lowest distortion in stereo reception - in particular, minimum inter-modulation between high audio frequencies and the 19 kHz stereo pilot tone.

WIDE STEREO SEPARATION

It is important to maintain wide stereo separation at low and high frequencies as well as the commonly- specified 1 kHz midrange point. in the 4020A, phase shift of the composite signal is minimised in order to preserve full low-frequency separation, and a special NAD phase-compensated crosstalk cancellation circuit increases high-frequency separation and minimises any residual distortion.

Instead of a costly and fragile moving-coil tuning meter the 4020A has a set of three LED indicator lights which form a remarkably simple and accurate meter. Either of two amber LEDs illuminates when the 4020A is mistuned to either side of a station frequency, and a green LED illuminates when the station is optimally tuned for minimum distortion (within 0.025 MHz). The brightness of the green tuning LED indicates the signal strength; when it is dim the station is too weak for optimum reception.

For the music lover seeking uncompromised performance for a modest investment, the NAD 4020A is the logical choice. There are more costly tuners available, some of which have more impressive specifications, but very few sound better in everyday use.

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NAD brochure 4020A AM/FM Tuner, Date of manufacture ? Jan, High Sensitivity, Wide Stereo Separation

4020A specifications

The NAD 4020A is a highly regarded amplifier that has earned a loyal following among audio enthusiasts since its release. Known for its solid performance and impressive sound quality, the NAD 4020A has become synonymous with reliability and affordability in the world of high-fidelity audio equipment.

One of the standout features of the NAD 4020A is its power output. The amplifier boasts a robust power rating, delivering a clean and dynamic audio performance that easily fills a room. With an output of approximately 20 watts per channel into 8 ohms, it is perfectly suited for driving a variety of speakers, from bookshelf models to more substantial floor-standing designs. Despite its relatively modest power rating compared to larger amplifiers, the NAD 4020A demonstrates a remarkable ability to handle peaks in audio without distortion, ensuring a clear and enjoyable listening experience.

Another notable characteristic of the NAD 4020A is its advanced circuit design. The amplifier employs a unique current feedback circuit topology, which contributes to its exceptional clarity and response. This technology allows the unit to maintain a linear frequency response across a wide sonic range, ensuring that both high and low frequencies are reproduced accurately. Furthermore, the NAD 4020A features low negative feedback, a design choice intended to preserve the natural character of musical instruments and vocals.

Build quality is also a strong point for the NAD 4020A. The amplifier is housed in a sturdy chassis designed to minimize vibrations and external interference, thus enhancing overall audio fidelity. This attention to detail extends to its internal components, where NAD utilizes high-quality capacitors and resistors that further improve signal integrity and reliability.

Aesthetically, the NAD 4020A possesses a clean and timeless design that fits seamlessly into most audio setups. The front panel features straightforward controls, including volume and tone adjustments, making it easy for users to fine-tune their listening experience. Additionally, the amplifier is equipped with multiple input options, allowing users to connect various audio sources, such as CD players, turntables, and streaming devices.

In summary, the NAD 4020A is a well-rounded amplifier that combines power, innovative technology, and solid build quality. Its ability to deliver excellent sound reproduction while remaining user-friendly makes it a popular choice for both novice and experienced audiophiles. With its reputation for reliability and performance, the NAD 4020A continues to be a staple in the world of high-fidelity audio.