Infrasonic and Ultrasonic Filtering. Audio signals often are contaminated with interference at frequencies
below and above the audible range-turntable rumble, floor vibration, tonearm/ stylus resonance,
radio/TV interference, and home-computer static. Amplification of such signals would tend to waste
amplifier power, cause bass distortion due to excess woofer cone travel, and produce audible
intermodulation distortion. The precise, minimum-phase, audio bandpass filtering in the NAD 3020B and
3120 strips off such interference, preserving a clean musical waveform.
Wide Dynamic Range
The line-level inputs (Tuner, Aux, Tape) cannot be overloaded by dynamic signal peaks from a Compact
Disc player. The total dynamic range of the amplifier, 100 dB, exceeds that of any available program
source.
Musically Useful Tone Controls
Like every other aspect of the 3020B’s circuitry, its Bass and Treble controls have been designed to be
genuinely useful. They provide effective boost and cut at low bass and high treble frequencies, but they
don’t alter the tonal balance in the critical midrange the way many tone-control circuits do.
High-Voltage, High-Current Output Stage
While the 3020B/ 3120 is conservatively rated at 25 watts per channel, it behaves as if it were much
more powerful. Its high-voltage design yields an IHF Dynamic Headroom factor of 3 dB, meaning that
during musical transients this amplifier can deliver fully twice its rated power into an 8-ohm impedance.
Even more important for genuinely musical sound is the amplifier’s interface with the complex and
variable impedances of real loudspeakers, which often are much lower than 8 ohms and are partly
“reactive” with high peak current demands. To supply this current to the speakers, the 3020B/3120
employs the same large output transistors that other manufacturers use In their “60-watt” amplifiers.
During musical transients the circuit easily delivers over 55 watts/channel into a 4-ohm impedance and
over 70 watts/channel into 2 ohms, with no protection- circuit distortion. NAD was the first
manufacturer to emphasise the importance of output current capacity, and this power reserve has
become increasingly important with the advent of advanced recording technologies that preserve the full
dynamic range of live music.
Binding-post Speaker Terminals
Heavy-duty binding posts provide secure low-resistance connections for all types of speaker cable. Their
standard s/a” spacing fits dual-banana plug connectors, facilitating quick reconnect ions among multiple
pairs of loudspeakers.
Soft Clipping™
When the NAD 3020B/3120 amplifier is over-driven beyond its power capacity, 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 high-order distortion that hard clipping normally would cause. Thus the amplifier can safely be over-
driven substantially beyond its rated power on peaks, and it will continue to sound smooth and musical.
Impedance Selector
Any amplifier is basically an electronic valve, passing power from the power supply to the loud-speaker
on demand, and so the voltage and current reserves of the power-supply circuit play a major role in the
amplifier’s performance. NAD’s unique impedance selector matches the amplifier to the loudspeakers.
One setting of this switch provides increased output voltages for loudspeakers of 8 ohms or higher
impedance. The other setting provides the lower volt-ages and greater output current needed to drive
low impedances (4-ohm speakers or two pairs of speakers wired in parallel).
The amplifier will even drive a 2 ohm load comfortably.
NAD Makes High Performance Affordable Designed with thoughtfulness and care rarely found in budget
components, the Models 3020B and 3120 amplifiers will drive the very best loudspeakers with ease and
will do justice to the finest musical recordings.
The NAD 3020B and 3120 amplifiers are complemented by the NAD 4020B AM/FM stereo tuner. A
separate NAD 102OB pre-amplifier is also available.
