1. INTRODUCTION
The NAD Model 118 Digital Pre-amplifier is different
from conventional pre-amplifiers, both in the way it
works and the features it offers. For a good under-
standing of this extraordinary pre-amplifier it can be
useful to be familiar with some of the principles behind
Digital and Analogue sound and signal processing. The
following brief explanation can be of some help but is
by no means complete.
Sound can be stored and reproduced in analogue or
digital form. Analogue storage of sound means that the
storage format follows exactly the pattern of the music;
e.g. a record groove is an exact representation of the
sound it stores. Similarly, sound can be processed
(adding or subtracting bass and treble, changing vol-
ume, etc.) in an analogue fashion, where the electrical
signal is again an exact representation of the sound.In
digital form, sound is stored or processed in a way
which isn’t an immediate representation of sound; e.g.
antique music boxes use a bar with many pins on it; by
rotating this bar each pin triggers a series of blades in a
specific sequence which then resonate, which we per-
ceive as music. The bar with pins is in fact a digital way
of storing music. Today, digital storage of music is
done by transforming the analogue signal into a string
of 0’s and 1’s, like computer language.
The whole process of storing and processing music
in a digital form is in fact very similar to the way a per-
sonal computer processes and stores its data. The
process of transforming an analogue signal into a digi-
tal signal is known as “Analogue to Digital conversion”.
For formats (such as CD) which carry the music in a
digital form, this conversion was done during the
recording or mastering process. Recordable digital for-
mats (such as DAT, DCC and MD) can take digital data
from a CD player direct but often have an A-to-D con-
verter (known as ADC, Analogue to Digital Converter)
built in to cope with analogue sources. The quality of
the ADC plays a large part in the total sound quality.
Digital storage and processing of sound has several
advantages; digital storage formats take up less space
for the same amount and quality of sound when com-
pared to its analogue counterparts and is, in general,
less prone to degradation over time or through wear
and tear. In the digital domain the sound signal can
also be more elaborately processed without any of the
artifacts analogue processing would bring.
Sound itself and the way we hear it is, is an entirely
analogue process which means that sound stored in a
digital form must be converted to back analogue before
we can hear it. Most CD players, DAT, MD, DCC
recorders, etc. have a Digital to Analogue Converter
(known as DAC) built in. Many also have a digital out-
put so an external DAC or processor (such as in the
NAD Model 118) can be used. As with ADCs, the quali-
ty of the DAC is crucial to the quality of sound.
The NAD Model 118 does all its sound signal pro-
cessing (volume, tone controls, compression, expan-
sion, stereo simulation, etc.) in the digital domain.
Processing in the digital domain is also referred to as
DSP (Digital Signal Processing). The Model 118 has
ADCs and DACs built in which means it can cope with
sound sources in either digital or analogue form. There
are 8 inputs in total; 4 for digital sources and 4 for ana-
logue sources.
2. INSTALLATION: REAR PANEL
CONNECTIONS & CONTROLS
The numbers refer to the rear panel drawing unless
stated otherwise.
This unit may be installed on any level surface that is
strong enough to support its weight. Due to the
advanced and comprehensive digital circuitry within the
NAD 118 there may be interference with radio recep-
tion, particularly if an indoor antenna is used and if the
tuner is positioned directly on top of or beneath the
NAD 118. In such instances use an outdoor antenna
with high quality coaxial cable and move the tuner fur-
ther away from the pre-amplifier.
Allow adequate ventilation. Do not place the unit on
a soft surface like a carpet. Do not place it in an
enclosed position such as a bookcase or cabinet that
may impede the air-flow through the ventilation slots.
CAUTION: The pre-amplifier must always rest on its
bottom feet. Never put the pre-amplifier down on its
rear panel, with its front panel facing up. Doing so risks
damage to the input/output connectors.
CAUTION: To prevent a fire or shock hazard, do not
permit liquid or moisture to enter the pre-amplifier. If
liquid is accidentally spilled on it, unplug the AC power
cord immediately. Do not open the pre-amplifier, or
attempt to modify or repair it yourself. There are no
user serviceable parts indside. Refer all servicing to a
qualified technician.
AC POWER CORD CONNECTOR (1).
Plug the AC power cord into a live wall socket. A
notice printed on the rear indicates the AC power-line
voltage that the Model 118 requires. In almost all cases
only versions with the correct voltage settings for the
country of purchase are supplied.
Note: Every Model 118 pre-amplifier has a “universal”
power supply that can be modified for operation in most
other countries. If you wish to transport your Model
118 to a country that employs a different power-line
voltage, an authorised NAD dealer or service agency
can convert it for such use. When you arrive at your
destination you can have the appropriate AC power
cord and/or plug fitted by an authorised NAD dealer or
service agency for local electrical outlets.
ANALOGUE SOURCE INPUTS & RECORDING
OUTPUTS (8 to 14)
The NAD Model 118 has the provision for 8 signal
sources; up to 4 digital and 4 analogue sources can be
connected; each with their own input jacks (and output
jacks for recorders) and input select buttons on the
front panel and remote Control handset. Analogue sig-
nal sources have separate RCA plugs for Left and
Right for a stereo signal. On most equipment and
cables the Left and Right channels are colour-coded:
White or black for the Left channel; Red for the Right
channel. When making connections make sure you
connect the Left and Right channels correctly.
NOTE: Before making any connections make sure
that the pre-amplifier and all other ancillary equipment
is switched off (particularly outboard Digital-to-
Analogue converters and power amplifiers).
NAD
6
GB