NAD 7120 - AC Power and Convenience Outlet; Front Panel Controls and Features; Power and Headphone Operations; Tone and Balance Adjustments

lf
the impedance
switch is
set to HIGH
(g
oHMS) when
you
are
using low-impedance
speakers,
or with
two
pairs
of
speakers
connected, lhe7120
may overheat
when
operated
at high volume
levels.
Prolonged
abuse
of this kind
could
cause internal fuses
to
blow in
order
to
protect
the receiver,
in
which
case
you
would
have
to return
lhe
7120
to
your
dealer for
service.
9.
AC
POWER
CORD. After
you
have
completed
mak-
ing
connections
to the
speakers
and
to
other system
compo-
nents,
plug
the AC
power
cord into
a
"live"
wall
socket.
10.
UNSWITCHED
AC
OUTLET.
(Not
in
U.K.
modet.)
The
AC
power
line
cord
ol another
stereo
component,
such
as a turntable
or tape
deck,
may
be
plugged
into
this acces-
sory outlet. This
outlet remains
"live"
as long
as the 7120's
power
cord is
plugged
into
a wall
socket.
FRONT
PANEL
CONTROLS
1.
POWER.
Depress
this
button
to switch
on
the re-
ceiver. The
green
LED
above
the tuning
presets
will
illumi-
nate when
the
power
is
on. To
switch the
power
off,
depress
the POWER
button
again
and release
it.
lf
you
prefer,
you
may
leave
the receiver's
POWEFI
switch
permanently
engaged
and use
an
external
switch
(such
as a clock timefl
to turn
the
power
on and
oft.
2. PHONES.
Plug
stereo headphones
in here.
The
circuit will
provide proper
drive
signals for
all conventional
stereo headphones
regardless
of
their
impedance,
with
just
one exception:
electrostatic
headphones
usually
are
sup-
plied
with
an adapter
unit which
must
be
connected
directly
to the
speaker terminals
on the rear
panel.
When
a headphone
plug
is inserted
into
the PHONES
socket the loudspeakers
are
automatically
shut
off.
lf
you
want to listen
to
speakers,
you
must
remove
any
plug
from
the socket.
Before
plugging
conventional
headphones
into
the
PHONES
jack,
turn
down the VOLUME
control
for
safety.
And when
you
are
not
listening
to the
headphones
it is
wise to
unplug them from
the
socket.
Otherwise,
when
not
listening
to the
phones
you
might inadvertently
turn up
the
volume
to
a
level
which
would feed
excessively
strong
signals
to the headphones
and damage
them.
You may
freely
use headphone
extension
cables.
lf
you
want
to use a headphone
Y-connector
to
drive two
headsets
simultaneously,
they
should
be identical
models.
Connecting
together
two headphones
which
differ widely
in
impedance
usually will
produce
a substantial
loss
of volume
in
the
headset
having
the higher
impedance
(or
in
both).
3. BASS. The
Bass
control
adjusts
the relative
level
of
the low frequencies
in the
sound. The
electrical response
ol the receiver
is flattest when
the
control is
set
in
the
detent
at the 12
o'clock
position.
Rotation
of the knob
to the
right
(clockwise)
increases
the level
of
low-frequency
sounds,
and rotation
counter-clockwise
decreases
their level.
Adjust
it
to achieve the
tonal
balance that
sounds
most natural
to
you.
You will
note that
at moderate
rotations
away from
center the
effect of the Bass
control is
subtle
because its
action is
confined
to the lowest
audible frequencies
where
significant
energy is
seldom found
in recordings.
Only at
large
rotations
away from
center is
there
a
substantial
boost
or cut
at the mid-bass
frequencies
which
are common
in music.
4. TREBLE.
The
Treble
control
adjusts
the relative
level
of the high
frequencies
in
the sound.
The response
of
the receiver
is flattest
when
the
control is
set in the
detent
at the 12
o'clock
position.
Rotation
ol the
knob to
the right
(clockwise)
increases
the level
of
high{requency
sounds,
and
rotation
counter-clockwise
decreases
their level.
Adjust
it to
achieve the
tonal balance
which
sounds most
natural
to
you.
You will
note
that boosting
the Treble
increases
the
brilliance
and clarity
ol details in
the
sound,
but also
makes
any
noise
more
prominent.
Turning
down the Treble
makes
the sound mellower
while
suppressing hiss
and record
surface noise,
but
too much
Treble roll-off
will make
the
sound
dull.
5. BALANCE.
The BALANCE
controt
adjusts the
reta-
tive
levels
of the
left
and
right
channels. A
detent
at the 12
o'clock
position
marks
the
point
of
equal balance.
Rotation
of the knob
to the right
(clockwise)
decreases
the level
ol
the lelt
channel
so that only the
right
channel is
heard,
thus
shifting
the
sonic
image
to
the right. Rotation
of the knob
to
the left
shifts the
sonic image
toward
the lelt
speaker.
ldeally
the detented
center
position
of the BALANCE
control will
be the normal
setting. But
several
common
circumstances
may
cause
unequal
balance, requiring
a
compensatory
off-center
BALANCE
setting
to restore
the
most
uniform
spread of
stereo sound
between
the
speakers.
These
include
unequal
output from
the two
channels
of the
phono
cartridge,
different
acoustical
environments
around
the two loudspeakers,
or simply
a listening
position
that is
closer
to one speaker
than
to the
other.
Adjust the
BALANCE
control
to
produce
a natural
spread
of sound
across the
space
between
the speakers,
with
any monophonic
sound
(such
as
a
radio
announcer's
voice)
appearing
as
a
phantom
image
centered midway
between
them.
6. VOLUME.
This
control
adjusts
the overall loudness
level
of the
sound. lt has no
effect
on the level
of the
signals
fed to
the BECORD
jacks
for
tape recording.
The
VOLUME
control is
designed for
accurate tracking
of
its
two
channels,
so that
the stereo
balance will not
shift noticeably
as the
loudness
of the
sound is varied.
7.
LOUDNESS
COMPENSATION.
Pressing
this
button
engages a
"loudness
compensation"
circuit
which,
at
low-to-medium
settings of the VOLUME
control,
boosts
the
low-bass
response
of the
receiver
in
order
to compensate
for the human
ear's diminished
sensitivity
to low-frequency
sounds
at low loudness
levels. The
circuit also
provides
a
slight treble
boost to
overcome the
"masking"
of subtle
high{requency
details
by background
noise.
The loudness-
compensation
circuit in the 7120
is more
subtle
in its action,
and thus more
realistic in
psycho-acoustic
terms, than
similar
circuits in
other
receivers.
L
BASS
EOUALIZATION.
This
circuit
boosts
the
lowest
bass frequencies,
those
below
60
Hz.
ln virtually
all
loudspeakers
the useful
output rolls
off at frequencies
below
the woofer/cabinet
resonance
(which
typically
occurs
be-
tween 40
and 70 Hz). The
BASS
EQ
circuit compensates
for
this roll-off,
extending the
useful response
of the speakers
significantly
lower in frequency.
Of course very low
frequencies
are not found
in
all
music,
nor in
all
recordings,
so the
effect of the
bass equal-
ization
olten won't
be obvious.
Sometimes
you
may find
that
switching
it in
and out does not
produce
any notice-
able change in
the
sound
whatsoever,
simply
because
the
recording
contains no
energy at very
low frequencies.
But if
your
loudspeakers
are capable
of
reproducing
low
bass,
and
if
you play
recordings
in which
low
bass does have
an
important
role, the BASS
EQ will
make
an audible
(and
occasionally
dramatic)
difference.
lf
your
loudspeakers
already have
extended
and
powerful
deep-bass response,
the BASS
EQ will
still be
useful to
correct for the
bass roll-offs
engineered into
some
recordings.
lt
also
works
well
in
combination with
the LOUD-
NESS
COMPENSATION
circuit to restore
subjectively flat
frequency
response
when
you
listen
to music
at low
volume
levels.
GAUTION:
Be
prepared
to switch
off the equalization
when
playing
recordings
(especially
digitally mastered
discs) that contain
unusually
potent
recorded
bass.
The
BASS EQ
boosts deep
bass
levels
by
5 dB,
i.e.
by a
factor
of
three
in
power.
lf
this boost is
combined with high-volume
playback
levels,
a bass-heavy input
signal
may
overdrive
the
amplifier into
clipping and-more important-overdrive
1
t
l
l