NAD 4020A User Manual

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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note that this document contains the text from the original product brochure, and some technical statements may now be out of date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, moderatelypriced 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 highperformance “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 commonlyspecified 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.

FM TUNER SECTION

 

 

Input sensitivity

Mono -30dB THD+N

10.9dBf (1.9µV/75Ω )

 

Mono 50dB S/N

16dBf (3.5µV/75Ω )

 

Stereo 50dB S/N

37dBf (40µV/75Ω )

Capture ratio (45 - 65dBf)

 

1.5dB

AM rejection (45 - 65dBf)

 

60dB

Selectivity

 

65dB

 

 

 

Image rejection

 

50dB

I F rejection

 

75dB

Harmonic distortion

Mono

0.2%

 

Stereo

0.3%

Signal/Noise ratio

Mono

75dB

 

Stereo

70dB

 

 

 

Frequency response ±0.5dB

 

30Hz - 15kHz

Channel separation at 1kHz

 

42dB

 

 

 

AM TUNER SECTION

 

 

Usable sensitivity

 

250µV

Selectivity

 

30dB

 

 

 

Image rejection

 

50dB

I F rejection

 

40dB

 

 

 

Remote

 

No

NAD Link

 

No

 

 

 

PHYSICAL SPECIFICATIONS

 

 

Dimensions (W x H x D)

 

420 x 96 x 240mm

Net weight

 

4.2kg

Shipping weight

 

5.6kg

Dimensions are of unit’s cabinet without attached feet; add up to 18mm for total height.

Dimension depth excludes terminals, sockets, controls and buttons.

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