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Details input sensitivity for mono and stereo reception.
Specifies capture ratio for AM rejection.
Details AM rejection ratio for signal clarity.
Lists selectivity performance metrics.
Specifies image rejection capabilities.
Details intermediate frequency rejection.
Provides harmonic distortion figures for mono and stereo.
Lists signal-to-noise ratio for mono and stereo.
Defines frequency response range.
Specifies channel separation at 1kHz.
Details usable sensitivity for AM reception.
Lists selectivity performance for AM.
Specifies image rejection for AM.
Details intermediate frequency rejection for AM.
Indicates remote control functionality.
Notes NAD Link connectivity.
Lists physical dimensions (W x H x D) of the unit.
Specifies the net weight of the tuner.
Details the shipping weight of the product.
Details input sensitivity for mono and stereo reception.
Specifies capture ratio for AM rejection.
Details AM rejection ratio for signal clarity.
Lists selectivity performance metrics.
Specifies image rejection capabilities.
Details intermediate frequency rejection.
Provides harmonic distortion figures for mono and stereo.
Lists signal-to-noise ratio for mono and stereo.
Defines frequency response range.
Specifies channel separation at 1kHz.
Details usable sensitivity for AM reception.
Lists selectivity performance for AM.
Specifies image rejection for AM.
Details intermediate frequency rejection for AM.
Indicates remote control functionality.
Notes NAD Link connectivity.
Lists physical dimensions (W x H x D) of the unit.
Specifies the net weight of the tuner.
Details the shipping weight of the product.
The NAD 4020A is a rationally-engineered AM/FM tuner designed to deliver high-quality audio performance at a modest price point. Its primary function is to receive and decode AM and FM radio broadcasts, providing an audio output that is intended to be audibly identical to more expensive tuners in most common reception conditions. The design prioritizes sound quality, aiming to ensure that the listening experience is limited only by the quality of the transmitted broadcast itself.
The tuner incorporates recent advancements in FM tuner circuitry, particularly utilizing inexpensive but high-performance "building block" circuit modules. This approach allows the 4020A to achieve excellent sound reproduction without the high cost often associated with elaborate designs. Key design parameters such as sensitivity, low distortion, and wide stereo separation have been given precedence. The designers deliberately avoided including costly, superfluous features and esoteric circuitry that would offer no audible benefits except in extreme and uncommon reception scenarios. However, no compromises have been made in performance areas that directly impact the tuner's listening quality in normal, and even somewhat challenging, reception environments.
For high sensitivity, the "front end" tuning circuit employs a Junction FET amplifier. This component is chosen for its optimal combination of sensitivity to weak signals and its resistance to cross-modulation from strong signals, ensuring clear reception even in areas with varied signal strengths. The intermediate frequency (I.F.) amplifier, a high-gain integrated circuit, contributes to excellent limiting, which is crucial for static suppression. It also provides very good AM rejection, effectively suppressing multipath interference, and ensures smooth muting of interstation noise, leading to a more pleasant listening experience between stations.
Regarding low distortion, a common area where budget-priced tuners often cut corners, the NAD 4020A distinguishes itself by employing a total of three ceramic I.F. filters. This is a significant improvement over the one or two filters typically found in similarly priced tuners. These filters are instrumental in providing sharp selectivity, which minimizes interference from adjacent stations, a growing concern on increasingly crowded FM dials. Furthermore, their linear-phase response contributes directly to minimizing distortion in stereo broadcasts, ensuring a more accurate and faithful reproduction of the original audio.
Multiplex stereo decoding is handled by the latest phase-locked loop (PLL) IC. This advanced decoder is chosen not only for its low noise characteristics and wide stereo separation but also for its ability to yield the lowest distortion in stereo reception. A particular benefit of this PLL decoder is its minimization of inter-modulation between high audio frequencies and the 19 kHz stereo pilot tone, which can otherwise introduce unwanted artifacts into the sound.
Maintaining wide stereo separation is another critical aspect of the 4020A's design. It is important for the tuner to preserve wide stereo separation across the entire audio frequency range, including low and high frequencies, not just at the commonly specified 1 kHz midrange point. To achieve this, the 4020A minimizes phase shift of the composite signal, which helps to preserve full low-frequency separation. Additionally, a special NAD phase-compensated crosstalk cancellation circuit is incorporated. This circuit enhances high-frequency separation and further minimizes any residual distortion, contributing to a more immersive and accurate stereo image.
For user convenience and accuracy in tuning, the 4020A foregoes a costly and fragile moving-coil tuning meter in favor of a set of three LED indicator lights. This system forms a remarkably simple yet accurate visual meter. When the tuner is slightly mistuned to either side of a station frequency, one of two amber LEDs will illuminate, guiding the user towards the correct tuning point. A green LED illuminates when the station is optimally tuned for minimum distortion, specifically within a very precise 0.025 MHz range. The brightness of this green tuning LED also serves as an indicator of signal strength; if the LED is dim, it suggests that the station's signal is too weak for optimum reception, providing useful feedback to the user.
In summary, the NAD 4020A is presented as a logical choice for music lovers who seek uncompromised audio performance without a significant financial investment. While more costly tuners with potentially more impressive specifications exist, the 4020A is engineered to sound equally good, if not better, in everyday listening situations, making it a practical and high-value option for radio enthusiasts.
General| Tuning Bands | FM, MW |
|---|---|
| FM Tuning Range | 87.5 - 108 MHz |
| Signal-to-Noise Ratio (FM) | 70 dB |
| Selectivity (FM) | 60 dB |
| Selectivity (MW) | 30 dB |
| Frequency Response (FM) | 30 Hz - 15 kHz |
| Stereo Separation | 40 dB |
| Dimensions | 420 x 96 x 240 mm |
| Power Supply | 220V |
| Sensitivity (MW) | 30 µV |
