The NAD
4020A is a rationally designed and built, at moderate price, 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 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 rxtreme
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-price 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 respponse 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 9within 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.
Specifications
FM Tuner
Section
Input
Sensitivity
Mono -30db
Total Harmonic Distortion+N : 10,9 dBf
(1,9 µV/75 Ω)
Mono 50 dB
S/N : 16 dBf (3,5 µV/75 Ω)
Stereo 50 dB
S/N : 37 dBf (40 µV/75 Ω)
Capture
ratio : 1,5 dB (45 - 65 dBf)
AM
Rejection: 60 dB (45 - 65 dBf)
Selectivity: 65 dB
Image
Rejection: 50 dB
IF
Rejection: 75 dB
Harmonic
Distortion:
Mono : 0,2%
Stereo
: 0,3%
Signal-to-Noise
Ratio:
Mono : 75 dB
Stereo
: 70 dB
Frequency
Response: 30 Hz - 15 kHz ±0,5 dB
Channel
Separation: 42 dB (at 1 kHz)
AM Tuner
Section
Usable
Sensitivity: 250 µV
Selectivity: 30 dB
Image
Rejection: 50 dB
IF
Rejection: 40 dB
Other
Power
Rating: 220 V, 50 Hz or 110 V, 60 Hz
Dimensions
(W x H x D): 420 x 96 x 240 mm
Weight
[Net/Shipping]: 4,2 kg / 5,6 kg