NAD 10 20 B - Manual

1020B Stereo Preamplifier
Date of manufacture : Jan 85 - Jan 87
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note that this document contains the text from the original product brochure, and some technical statements may now be out of date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 1020B continues the NAD tradition of remarkable price/performance value. An audiophile-quality
preamplifier at an extraordinarily low price, the NAD 1020B is derived from the design of the pre-amp section in the
renowned NAD 3020B integrated amplifier. It is the optimum choice for listeners who wish to combine the
simplicity and acclaimed performance of the 3020B with a much larger power amplifier, a bi-amplified system, or
active powered loudspeakers. The surprisingly low price of the NAD 1020B pre-amp, together with the modest cost
of several “best buy” power amplifiers in today’s marketplace, substantially reduces the entry cost into high-
performance separates for many audiophiles whose choice would otherwise be limited to integrated amplifiers and
receivers. Do not be deceived by the 1020B’s external simplicity and bargain cost; this is not a compromise product,
nor a halfway step toward high-quality sound. Its economy results from spartan cosmetics, canny engineering,,
efficient manufacturing, modest input/output flexibility, and the elimination of seldom- used features. Behind its
modest faceplate the 1020B’s circuitry-and its sonic performance-are the equal of most preamplifiers costing two or
three times more, Circuit Features Wide-Range Phono Preamplifier. As long as phonograph records remain the
primary high-quality music source for most listeners, the phono pre-amp stage will be the heart of any good
preamplifier-its most important circuit and potentially its weakest link.
Instead of the usual low-cost IC, the phono preamplifier section of the 1020B is a newly designed discrete-transistor
circuit whose performance matches that of far more expensive pre-amp systems: 0 It interfaces correctly with the
high impedance of the moving-magnet pickup cartridge (as many costlier preamplifiers do not), avoiding complex
impedance interactions that can alter the pickup’s frequency response.
• Its input capacitance is switch-selectable, allowing you to provide the loading that the cartridge needs for flattest
response.
• its precise RIAA equalisation preserves the exact frequency response of your cartridge.
• Its signal to noise ratio is optimised, not for the usual short-circuit input, but for the typical impedance of real
magnetic cartridges. As a result its residual circuit noise is close to the theoretical limit set by the cartridge itself
(the “thermal” noise due to the pickup’s own impedance). This ensures that the preamp’s noise will be inaudible
even when you are playing the widest-range direct-to-disc and digitally mastered discs.
• For low-output moving-coil cartridges a rear-panel switch resets the preamp’s parameters to provide the required
20 dB of added gain with extremely low noise-lower than that of many external pre-preamplifiers, while
avoiding the high cost and hum problems of step-up transformers.
• The circuit’s distortion remains extremely low, not only with simple sine-wave test tones but also when
reproducing the most complex and demanding high-level waveforms that a cartridge can generate. The circuit’s
output stage has ample headroom for the amplified musical waveform and also provides plenty of current to
drive the reactive RIAA feed-back network without strain.
• The dynamic range of the phono stage, over 107 dB, is ample for the widest-range digitally mastered recordings.