dbx 3BX - Maximum Output Level; L.E.D. Display; Output Clamp; Tone Burst Response

12)
Maximum
Output
Level
12.1)
With
the
remote
switch
on
3BX
in
the
"out
position,
<
set
the
oscillator
to
1
khz
<a
+
lOdB
and
increase
the
output
level
of
the
test
unit
(full
expansion
)
by
adjusting
the
transition
level
control
until
clipping
of ^
the
waveform
is
observed
on
the
oscilloscope.
A
"7
volt
RMS
20V
P-P)
output
should
be
achieved
before
clipping
occurs,
and
the
waveform
should
clip
symmetrically
-
13)
L.E.D.
Display
13.1)
With
an
input
of
+ 10
dBv
at 1
khz
and
expansion
control
at
1.5,
move
the
transition
control
from
left
to
right
and
ensure
that
the
leds
turn
on
in
sequence.
With
transition
level
fully
to
the
right,
all
the
red
leds
should
be
lit.
At
no
time
should
two
leds
turn
on
at
the
same
time,
nor
should
a
red
and
yellow
led
be
lit
simultaneously.
(Some
yellow
leds
should
be
lit
in
both
the
high
and
low
band
and
occasionally
in
the
midband
with
the
threshold
control
fully
to
the
left.)
13.2)
With
the
transition
control
fully
to
the
left
and
both
inputs
shorted,
move
the
expansion
control
from
1.0
to
1.5
and
observe
that
the
yellow
leds
turn
on
in
sequence.
As
the
expansion
control
is
moved
to
the
right,
all
three
bands
should
have
their
yellow
leds
light
approximately
at
the
same
time.
With
the
expansion
control
fully
to
the
right
and
the
transition
control
fully
to
the
right,
all
the
yellow
leds
should
be
lit.
Check
to
make
sure
they
are
all
the
same
color.
With
a
shorted
input
and
both
the
transition
and
expansion
controls
fully
to
the
left,
no
leds
should
be
lit.
Adjust
if
necessary.
14)
Output
Clamp
14.1)
When
the
power
switch
is
activated,
a
brief
pause
should
be
observed
on
the
oscilloscope,
before
the
output
climbs
to
it's
correct
level.
15)
Tone
Burst
Response
15.1)
With
a
tone
burst
input
of
8
cycles
on,
128
off
and
the
expansion
control
set
to 1.5,
check
that
the
output
as
observed
on
the
oscilloscope
resembles
the
drawings
provided
for
200
Hz,
700 Hz,
3
khz
and
7 khz
for
both
channels.
Transition
control
may
be
adjusted
to
get
the
correct
wave
shape.