Specifications

Controls & Connectors
7
Front Panel
Figure t shows the
panel
layout
of the AN30O2. The
funclions
ofthe controls and indicators
are as follows:
l. Attenuator
Level controlforyouramplifier
is
provided
by a 21
position
detented
potentiomelerand
indicates
gain
reduction in decibels from the 0 dB
position
(maximum
gain,
no attenualion).
2. VU Meter
-
Status Indicator
Level Indication
(see
inselt -
l)
Each channel featuresa variable 1
0segmentdisplay
showing
lhe actual
power/volume
level available
before clipping
(taking
mains supply
and
load duty
into account).
The display is colourcoded, and calibrated in 3dB
increments.
The 10 LEDS are:
Green
=
-27dBlo-21d8
Yellow
=
-18d8
to
-6dB
Red
=
-3dB
andthetwo
LEDS indicating
the clipping
point.
Power
On
Indication
Two
Green LEDS either side of the mains switch
(above
the "ON" legend) are used to indicate that
the unit is on. The first Green
LED indicatesthe 15
Volt
preamp
supply is
present
(the
len
hand side
display shows
-15V,
andthe right hand sideshows
the
+15V).
The next LED outwards is also a supply indicator
and
shows that the Positive High Current Outpul
Rail is available to the corresponding channel.
NOTE: Theamplifieris notdamaged by running into
clipping,
but
speakers
may be. To maximisethe life
ofyourspeekers,
try lo keep clipping infrequent.
3. Power Switch
Pressthe switch DOWN for
power
ON and
!,Pfor
power
OFF. At start-up
(turn-on)
the input to the
amplifier is muted by 30dB for approximately two
seconds.
4. Thennal
Indicator
When switching the amplifieron, this red LED
will
flash momentarily, indicating
conect operation of
the Mains ln-Rush Currenl Suppression circuit.
Aft erestablishment of lnrush Currenl Suppression
circuil the LED will extinguish. This LED will not
illuminate
during normal use of the amplifier.
ln the advent of a thermal overload this LED will
illuminate red indicating that the internaloperating
temperature ofone or both amplifierchannels has
exceeded a safe levelofoperation andthe amplifier
will be shutdown. The fanswill continueto run and
oncethe amplifierhascooled down sufliciently, the
amplifierwill s{art up automatically
providing
lnrush
Current Suppression
and input signal
muting until
establishment of the amplifier afler which it will
retum to normaloperating
mode.
NOTE:You should always ensurethatthe fan
grille
is
kept clean
and free
from the build up ofdust and
lint. Thiswill ensure longeroperation of
youramplifier
and reduce the
possibility
of it
prematurely going
intothermal shutdown mode.
5. Fault Indicator
ThisamberLEDwill illuminatewhen a fauttcondition
exists-
The fault detection circuit monitors the d ifference
between drive and output
in
youramplifier.
lfyou have a short circuit on the speakeroutput
(or
a blown negative railfuse)the LEDwillflash brightly
in sync with the
programme.
This LED will also
flashwith
programme peeksfor gross
overloads or
if lhe load
is
2 ohms
or
less.
The circuit hastwo stages of operation:
1 . ltwillprovide indication
(e.9.
grossoverload)
but
does not affect the input signal
(a
faint flash).
2. lt will indicate and mute the
input signal
(e.9.
shorted outpul)
(brightly
flashing or
permanently
on).
ln the advent ofa failurethe
display
panelrevertsto
a faull display to assist in diagnosis
of the fault.
-
The VU meterwill light up fully and the Positive
Output Rail LED will extinguish
if the
positive
supply rail is not available
(check
rear rail breaker).
-
The fault Led will
glow
brightly if the Negative
output Railis nol available
(check
rea r ra il breaker).
-
Failure of the
pre-amp
supply
will cause the
amplifier to be muted and indicator
LEDS to be
extinguished
Australian Mon'rtor
/tu