JBL 6230 - 3.3.1 ABOUT SENSITIVITY RATINGS

the
operator
to
take
appropriate
action.
This
LED will
remain on
long
enough
to
be
seen even
if
the
excess
signal
is
only a
brief
transient.
To
avoid
audible
distortion,
when
the
LED
indicator
flashes
more
than
occasionally,
either
lower
the
level
of
the
source
feeding
the
amplifier
or
turn
down
the
amplifier’s
Level
control.
Overload
conditions
are
monitored
separately
for
each
channel.
The
input
differential
amplifiers
are
of
sufficient
sensit-
ivity
to be
driven to
full
output by
any
medium
or
high
line
level
source;
an
input of
+3
dB (1.1
V
rms)
will
produce
rated
output
into
8
ohms.
The
Level
control
comes
after
the
input
stage.
Therefore,
signal
levels
up
to a
maximum
of
+20 dB
(7.75
V rms)
can
be
accomodated
without
overload.
There
is
little
likelihood
of
clipping
in
this
stage
without
at
the
same
time
clipping
the
output;
it
is only
possible
when
the
amplifier's
Level
control
is set
at
#28 or
lower.
The
symptom
of
such
input
overdrive
is
audible
distortion
without any
indication
from the
CLIP
LED. In
such
cases,
simply
lower
the
signal
level
at
the
source
and use a
higher
number
on the
amplifier's
Level
control.
3.3.1
ABOUT
SENSITIVITY
RATINGS
With
regard
to
sensitivity
ratings,
power
amplifiers
are
unique.
Other
audio
signal
processing
and
mixing
equipment
sensitivity
describes
the
average
input/output
level,
whereas
a
power
amplifier's
sensitivity
describes
the
input
signal
required
to
obtain
maximum
power
output.
Therefore,
if a
mixer,
equaliz-
er,
or
other
device
is
rated
at
+4
dB
nominal
output,
that
aver-
age
level
could
continuously
overdrive
the
power
amplifier.
This
is
why
a
level
control
is
provided
on
the
amplifier.
By
turning
down
the
level at
the
amplifier,
input
sensitivity
is
effectively
reduced
to
match the
source
so
that
onlv peaks
drive
the
amplif-
ier to
full
output.
With a
mixer,
equalizer,
etc.
rated
at
-10
dB to
-15
dB
nominal
output,
little
or no
attenuation
is
required
in
the
power
amplifier.
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