Specifications

Controls
&
Connectors 7
Front
Panel
The Pi
Series models
have
identical
front
panel
layouts.
Fig
u
re
7 shows
the
panel
layout
of
the
PlSeries.
The
fu
ndions of the
controls
and indicators
are
as
fol lows:
I Aftenuator
Level control
for
your
amplifier is
provided
by a
21
position
detented
potentiometer
and
indicates
gain
reduction
in
decibels from the 0
dB
position
(maximum gain,
no
attenuation).
2
Status
Indicator
This is
a dual
color LED
which displays the
status
of the output
stage
and displays three levels
of
operation.
These levels
are:
Below 1 watt (unlit)
1 watt
and above (green)
1dB below actual
clipping
(red)
The LED
will turn
green
once the output voltage
exceeds
2.828
volts
(1
watt
re 8 ohms or 2 watts
re 4 ohms).
This
is equivalent
to:
24dB below rated
powerfor
a PA800 or
26dB below
rated
power
for a PA1200.
The
LED will
change
to red once
the
output
exceeds the
-1dB
point
before actual
clipping
of
the amplifiefs
output
stage.
The threshold of
the
-1dB
point
is refened
to the
amplifier supply rails
and alters
with changes
in the mains supply,
changes
in the
load
and duty
cycle
fluctuations.
The
attack
and
decay
time
(ballistics),
of
the
status circuit
are those
of a Peak Programme
Meter
(P.P.M.)
:.
lf using this indicator
to line
up sensitivities, apply
a steady
state
tone
(e.9.
slate
on a mixing console).
The 1 watt
level
is the
mid-point
between
the
indicator
illuminating
and
extinguishing
green.
NOTE: The
amplifier
is
not damaged by running
into clipping,
but
speakers
may
be.
To maximise
the life
of
your
speakers,
try to keep clipping
infrequent.
3 Fault Indicator
This amber
LED will flash when a fault
condition
exists.
The fault
detection circuit monitors the
difference
between
drive and output in
your
amplifier.
lf
you
have a short
on
the
speaker output
(or
a
blown
negative rail fuse) the
LED will flash brightly
in
sync with the
programme.
This
LED will
also
flash
with
programme peaks
for
gross
overloads
or
if the load
is 2 ohms or less.
The
circuit has two
stages of operation:
1.
lt will
provide
indication
(e.9. gross
overload)
but does not
affect
the input
signal
(a
faint flash).
2. lt will indicate and mute the
input
signal
(e.g
shorted
output)
(brightly
flashing
or
permanently
on).
+
Power Switch
Press
the
switch
to
the
right
for
power
on
(
I
)and
to the left
for
power
off
(
0
).
At
start-up
(turn-on)
the
input
to
the
amplifier is
muted
by 30dB for
approximately
two seconds.
5
On/Thermal
Indicator
This is
a dual colored LED which
will
normally be
green
and indicates that
the amplifier is
on and
receiving
mains
power.
ln the advent
of a
thermal
overload
this LED will
tum
red indicating that the intemal
operating
temperature of one or
both amplifierchannels
has
exceeded
a
safe level
of operation
and the
channels
will be automatically
muted.
The fans
will continue to run and once
the
effected channel/
s have
had a cooldown
period,
theywill un-mute
and return
to
normaloperation.
NOTE:
You should always ensure
that the fan
grille
is kept
clean
and free from
the
build up
of
dust
and
lint. This
will ensure longer
operation
of
your
amplifier and reduce
the
possibility
of it
prematurely
going
into thermal
shutdown mode.
Aus;balian
Monitor.
/tu