NAD 7120 - Indicator Lights Explained; Important Operational Notes; Overload Protection and Speaker Impedance

15. FM
STEREO
BEACON.
This red
LED
ittuminates
when
a stereo FM
broadcast
is
being received
and decoded
by the receiver's
multiplex
decoder
circuit. lf
a station
is
broadcasting in mono,
or
if
a
stereo broadcast
signal is too
weak for reasonably
noise-free
reception
in
stereo,
then the
7120
will
automatically
switch into
mono
and this light
will
not
illuminate.
Also, if
you
have
mistuned
the receiver
away
from the
center
of a station's
broadcast
channel,
the stereo
decoding
circuits may not lock
onto the
signal
and it may
be
received
in
mono.
16. POWER
INDICATOR.
This
green
LED
iiluminates
whenever
lhe 7120 is
turned
on.
A
Note on Overload Protection.
Because the
NAD
7120 sounds
so clean and musical
when
driven
beyond its
nominal
power
rating
and
when
used to drive low-imped-
ance
loudspeakers,
you
may
be tempted
to stress it
beyond
its
design capacity. For
example
this
receiver
can safely
and
cleanly drive
a
2-ohm
load impedance,
reproducing
wide-
range musical
signals with
peak
levels
of 50 watts
or more.
Thus it is
permissible
to
play
music
at volume levels
which
cause the transient
peaks
and climaxes
to
exceed the
receiver's
rated
power
by a considerable margin,
and
with
Soft
Clipping
the
music
will
continue to
sound
good
at those
high
peak
levels.
But
if
you
overdrive the receiver
continuously rather
than
only on brief musical
peaks,
the output
transistors may
overheat. This is
particularly
likely if
you
set the
SPEAKER
IMPEDANCE
switch to
8 OHMS and then try
to drive very
low impedances
at high volume
levels.
Severe
abuse of this
type could
cause
internal
fuses
to blow in order
to
protect
the receiver. These
fuses
are
not
intended
to be replaced
by
the
user; if the receiver
shuts
down
you
should return
it
for service.
lf
this occurs,
you
should examine
whether a
pattern
of unintended
abuse may have
contributed to
the
failure.
For
example
you
may have
a
loose
strand of speaker
wire
causing
a
partial
short-circuit
either at the
speakers or at the
receiver's
speaker terminals.
The impedance
of
your
speak-
ers may
be
lower
than
you
think; if
you
are
not
sure,
set the
SPEAKER IMPEDANCE
switch to NORMAL
(4
OHMS). You
may
be combining maximum
bass boost with high volume
settings.
Or
you
may
simply be
playing
the music
at continu-
ously high
power
levels
that demand
a
larger
amplifier.