User Guide

AT250B
Power Amplifier
Product
Description
The AT250B
is
a 250 watt
po\rer
amplifier with
outputs fu 4
olrns, 70
and
100 volt line.
It
may be
desk m rack
mqmted
but
cmes
gandard
as
self
standing with rutrber
feet. The
AT250B featrres
a
flat
ssewdriver acc€ssible
gain
curtol
m
the
fimt
panel
and
a limit indication
LED. The
frctory
setting
for
the
front
panel gain
cmtrol
is
I volt RMS.
Units may
be stacked to
a
maximum
of3
uitshigh.
Front Panel
Controls
l.
Galn
Gontrol: Access is
via
the front
panel
using
a small flat head
screwdriver. Factay
pre-set
is 1 volt
RMS, the
sensitivety
of
the
amplifier may
be
reduced
by
turning the
gain
c,mtol in
a
counter-clockwise
direction, or increased
by turning
the
pin
cqrtrol in
a cloclnrise
directim
.
Llmlt
LED:
This
red LED is
desigred to
give
the user a
visual
indication
of
the
status of the
operating oonditim
of the
amplifier
and is integral
to
the inbuilt
prdectior
included
in the
amplifier. Dring ncmal
qleratim,
the LED
will flicker
oocasiurally,
however
if the LED
flickas
fm lemglhy
p€rids
m stays
cmtinuorsly
glolying;
this is an indicatiqr
that
the
amplifier
is
being
overdriven
by the
incming
program
sipal.
If
this input
ovenload cmditim is
cmbined with the maximum
load
m the output
of the amplifier then
the
amplifier will
autmatically shut itself
dffi'n fc a
period
of approximately
3 secmds
and then turn
itself back
on
agein
and continue
to
cycle
in
this
frstricr
until the
abnormal cmdition is removod.
This is a
feature
of the amplifier and is
desigred
to
prdect
the internal
circuity of the
amplifier and also to
prdes{
aoy speakers that
may be
cmnected
to the
ortput of the
amplifier.
Power Button: This
switch cqrtols
the
switching of AC
power
to
the anplifier. Roc{ring
this switch upwards
turns
on
AC
power
to the
amplifier while
rocking the
switdr
downwards
tums
pourcr
of to the a.mplifier.
When in
the
upward
position,
the red nem in
the
body
of
the switch
will
glow.
3.