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3020 series 20
Integrated Amplifier
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note that this document contains the text from the original product brochure, and some technical statements may now be out of date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 3020 is a no-frills moderately-priced amplifier designed to provide state-of-the-art performance
at volume levels far in excess of what would be expected from its conservative 20-watt per channel
power rating. This remarkable characteristic is made possible by high-voltage, high-current output stages
which can deliver short-term bursts of two to five times the rated continuous power output into
loudspeakers of widely varying impedances.
The 3020’s exclusive Soft Clipping™ circuit permits listening levels even beyond these limits by reducing
harshness at high volume settings.
The phono preamplifier section of the 3020 contains a sophisticated 6-transistor circuit which has been
engineered for extremely low noise and nearly distortion-free performance. Built-in infrasonic and
ultrasonic filters further reduce the interference of non-musical signals caused by turntable rumble, floor
vibration, tone arm or stylus resonances.
These uniquely designed input and output stages combine to create an inexpensive amplifier which is
easily capable of driving the very best loudspeakers.
EFFECTIVE CONTROL FEATURES
Like every other part of its design, the 3020’s controls have been carefully considered for genuine
usefulness. The Bass and Treble controls are tailored for musically effective response in the high and low
frequencies without altering the critical mid-range tonal balance.
For listening at low volume levels or with sensitive headphones, the 3020’s Audio Muting button
reduces levels by 20 dB, expanding the useful range of the Volume control and subduing any residual
circuit noise. A simple, elegant set of five LEDs accurately displays the peak power level which the
amplifier is delivering to the loudspeakers, from 1 to 35 watts into 8 ohms or 2 to 70 watts into 4
ohms. The circuit monitors both channels and displays the higher output at each instant.
DESIGNED FOR REAL-WORLD PERFORMANCE
If you read specifications tables and magazine test reports you will find that the majority of modern
amplifiers measure well on the test bench, with impressive figures for signal-to-noise ratio, power
output at 8 ohms, and ultra-low harmonic distortion, But outside the laboratory many of these products
don’t perform as well as their specifications suggest. In the home you don’t listen to signal generators
and 8-ohm test resistors, you listen to complex musical waveforms generated by phono cartridges and
reproduced through loudspeakers whose impedance is seldom 8 ohms Rather than incorporating costly
refinements that may test well, but yield little audible improvement, NAD’s engineers have designed the
3020 for optimum performance in everyday use.
HIGH-PERFORMANCE DESIGN
Wide Range Phono Preamplifier
In a moderately priced amplifier you might expect to find an economy preamp circuit, but the NAD
3020 contains a phono preamp stage which is audibly identical to the finest separate professional
preamps. The 3020 preamp interfaces correctly with the impedances of real phono cartridges (as many
preamps do not), it is quiet enough for use with either moving-magnet or high-output moving-coil
pickups, and its distortion is extremely low, not only with sine-wave test tones but also when
reproducing complex high-level music signals. The 3020 was designed to achieve the best signal/noise
ratio when a cartridge is plugged in (rather than with the usual, but inappropriate, short-circuit input).
The total dynamic range of the 3020 is typically 107dB, ample even for the digitally-mastered recordings
of the 1980s.
Infrasonic and Ultrasonic Filters
Audio signals are often contaminated with interference at frequencies below and above the audible
range, such as acoustic feedback, disc warps and radio interference.
Amplification of such signals yields no sonic benefit, wastes amplifier power, and may cause
intermodulation distortion muddy bass, excessive woofer cone motions, and even tweeter burnout. The
NAD 3020 contains a precise, minimum-phase audio-bandpass filter which strips off such interference
and preserves a clean musical waveform.
High-Voltage High-Current Output Stage
Although the 3020 is rated at 20 watts/channel, it behaves as if it were much more powerful. Its high-
voltage design yields an IHF Dynamic Headroom factor of 3.0 dB, meaning that in musical transients the
3020 can deliver twice its rated power or 40 watts into an 8-ohm impedance.
Even more important is the amplifier’s interface with the highly variable impedances of real
loudspeakers, which often are much lower than 8 ohms and partly “reactive” with high peak current
demands. The output transistors in the 3020 are the same large devices which other manufacturers
employ in their “60 watt” amplifiers, and in musical transients the 3020 will easily deliver over 58
watts/channel into 4 ohms or over 72 watts/channel into a low 2-ohm impedance, with no distortion
due to triggering of protection circuitry.
Soft Clipping™
When the 3020 amplifier is overdriven beyond its rated power, the exclusive NAD Soft Clipping™ circuit
gently limits the waveform voltage so that the output transistors are never driven into saturation, i.e.
into “hard clipping.” This feature eliminates the harsh power-supply buzz and some of the distortion
which hard clipping normally would cause, thus the 3020 can be overdriven substantially beyond its
rated power cleanly and safely.
Dual-Mode Power Supply
The power supply circuit for the output stage is only loosely regulated, so it is free to supply the high
voltages needed for a high IHF headroom factor (at 8 ohms) and also to supply the large currents at
lower voltages needed for driving low-impedance loads (down to 2 ohms). An entirely separate power
supply circuit, operating from another secondary winding on the power transformer, supplies extremely
stable, noise-free, regulated operating voltages for the preamplifier and tone control stages; thus
distortion and blurring of the stereo image due to power supply modulation cannot occur in the 3020.
The NAD 3020 has earned a world-wide reputation among audio reviewers for its sensible and efficient
design and superb performance.
Numerous test reports, comparing the 3020 with equipment of far greater power rating and cost have
proven the 3020 to be an outstanding value.
PRE-AMP SECTION
Phono input
Input impedance
(R and C)
Input sensitivity, 1kHz
Signal/Noise ratio
(A-weighted with cartridge connected)
Line level inputs
Signal/Noise ratio
(A-weighted ref 1W)
Channel separation
Frequency response
(20Hz - 20kHz)
Infrasonic filter
Ultrasonic filter
POWER AMP SECTION
Continuous output power into 8
Ω
*
Rated distortion
(THD 20Hz - 20kHz)
Clipping power
(maximum continuous power per channel)
IHF Dynamic headroom at 8
Ω
IHF dynamic power
(maximum short term power per channel)
47kΩ / 47pF
2.5mV ref. 20W
75dB ref. 5mV
>86dB
>60dB
±0.5dB
-3db at 15Hz, 24dB/octave
-3dB at 35 kHz, 12dB/octave
20W (13dBW)
0.02%
30W
+3dB
40W
58W
72W
No
No
420 x 96x 240mm
5.3kg
6.7kg
8Ω
4Ω
2Ω
Remote
NAD Link
PHYSICAL SPECIFICATIONS
Dimensions (W x H x D)
Net weight
Shipping weight
* Minimum power per chnnel, 20Hz - 20kHz, both channels driven with no more than rated distiortion.
Dimensions are of unit’s cabinet without attached feet; add up to 18mm for total height.
Dimension depth excludes terminals, sockets, controls and buttons.
© NAD Electronics. All rights reserved. E & OE

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