NAD L 40 Manuel D'installation page 12

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However, it is recommended that you switch the
unit totally off if it is not going to be used for more
than a couple of days. Switch off completely by
pressing the POWER button on the front panel (No.
1), all lights will extinguish.
VOLUME UP and DOWN buttons:
On the remote control handset there are two but-
tons for volume. Press the UP button to increase the
volume level; press the DOWN button to decrease
the volume level. When using either the DOWN or UP
volume control button on the remote control handset,
the display will indicate respectively "VOL DOWN" or
"VOL UP". The motorised volume control knob on
the front panel will move down or up at the same
time.
MUTE button:
By pressing this button the overall volume level is
significantly reduced (by 20dB). This can be useful to
quickly lower the volume level to answer a telephone
call, for instance. When the unit is muted, the display
indicates "MUTE", in whatever mode it is in.
Press MUTE again to restore the original volume
level.
STOP button:
Press this button to stop CD playback or to clear
"Program Play". On the front panel there is also a
STOP button which performs almost the same func-
tion as the button on the remote control handset,
however this button also opens or closes the CD tray
door.
CD, TUNER, AUX and TAPE buttons:
Unlike the front panel, the remote control handset
has separate buttons for each input. Press the corre-
sponding button for the desired input.
The PLAY/PAUSE, SKIP/PRESET, and DISPLAY
buttons function in the same manner as those with
the same name on the front panel of the unit (respec-
tively No's. 6, 7 and 14 on front panel drawing).
MAINTENANCE
At periodic intervals, open the disc drawer and wipe
with a damp cloth to remove any loose dust.
HANDLING COMPACT DISCS
Handle Compact Discs with care. The playback of
a disc will not be impaired by small dust particles, a
few light fingerprints, or slight scratches. But large
scratches, or a thick layer of oily fingerprints, can pre-
vent the player from tracking the disc. (Incidentally,
although the tracking laser 'plays' the disc through its
clear side, the actual data surface is embedded
directly beneath the label, protected only by a very
thin coating of lacquer. So a scratch that cuts through
the label may damage the disc more than a similar
scratch on the transparent 'playing' surface. Thus you
should treat both surfaces of the disc with care.)
Severe scratches or fingerprints may cause the
player to mis-track (skipping ahead, or repeating the
same passage). Less severe damage may produce
very brief bursts of high-frequency noise. The track-
ing and error-correction circuits of this NAD CD
NAD
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Receiver are unusually sophisticated, providing
secure tracking of flawed discs that are not playable
on some other players. Nevertheless, the discs
should not be abused or handled carelessly.
For best results, grasp the disc only by its edges.
Another safe method is to put a finger in the centre
hole, using the thumb at the edge to hold the disc
steady.
Each disc should be kept in its protective storage
case when not in use. To open the standard Philips-
type plastic CD case, grasp the top and bottom of the
case with the fingers and thumb of the left hand; then
grasp the left and right edges of the case with the fin-
gers and thumb of the right hand, and pull the case
open with the right thumb.
The disc is held in place within the case by an
expansion hub in its center hole. To remove the disc,
press the hub with a finger to release the disc, then
lift it out by gripping its edges between the fingers
and thumb. To replace the disc in the case, simply
align its center hole with the hub and press the disc
onto the hub.
CLEANING DISCS
Soiled discs may be cleaned by wiping with a soft
cloth, either dry or moistened with water. Do NOT use
conventional LP record-cleaning products (cleaning
solutions, sprays, treated cloths, or anti-static prepa-
rations), nor any kind of chemical solvent (alcohol,
benzene, etc). A severely soiled disc may be washed
in a warm-water spray, possibly with a small amount
of a mild kitchen detergent added, and then wiped dry
with a clean, soft towel.
When cleaning the disc, use only RADIAL strokes
(from center to edge). Never use a circular wiping
motion like that used for cleaning ordinary LP
records, because in wiping the disc there is a risk of
scratching it. A radial scratch will do the least harm
because it affects only a small portion of each circular
data track, which can be fully compensated by the
player's error-correction circuits. But a circular scratch
that follows a data track may damage such a long
continuous segment of data that it cannot be correct-
ed.
ABOUT THE LASER
The CD Receiver uses a solid-state semiconductor
diode laser, mounted on a tracking servo mechanism,
to play the disc. The laser illuminates the track of
microscopic pits representing the digital data bits,
while photo-diodes detect the reflected illumination
from the disc and convert it into an electronic signal
which is then decoded to recover the musical wave-
form in each stereo channel.
You cannot see the laser operating, because it
operates at wavelength of 7800 Angstroms, which is
in the infrared region and thus invisible to the human
eye.
The CD Receiver is completely safe for children to
use. The laser operates at very low power and is con-
cealed within the player mechanism. Even when the
player is disassembled, the laser remains sealed
within an optical system that causes its light to focus
only 1 millimetre from the lens and then diverge
rapidly, reducing its intensity to negligible levels.