Peavey PA 120 User manual

PA 120
The new PA-120 is a compact portable sound rein-
forcement MIXER/AMPLIFIER featuring a rugged 100
Watt
power
stage.
This
compact
but
powerful
unit
is
capable of handling most any club or lounge perfor-
mance
as
well
as
the
smaller
concerts.
Because
of
the
super
heavy
duty
silicon
output
devices
and
the
large
aluminum heat sink the PA-120 has the extra measure
of
durability
required
for
demanding
commercial
applications
The PA-120 is a four channel mixer/amplifier with the
capability of handling up to four microphones or
instruments because of its extremely wide dynamic
range.
Each
channel
of
the
120
features
separate
volume, bass, treble, and reverb controls to enable the
operator
to
control
each
microphone
or
instrument's
tone and response characteristics. The master section
of
the
PA-120
provides
overall
volume
and
main
reverb
controls for added flexibility. These master controls
enable the operator to more fully control the output in
order to create a more balanced sound. The reverb
effect is controllable from the optional remote
footswitch.
1. The volume control serves to vary the gain of the
preamp. The preamps of the new 120 PA are of the
variable feedback type which allow lowest noise and
maximum performance,
2. The reverb control is used to vary the amount of
reverb signal from the individual channels. The con-
tinuously variable control allows the operator to mix in
any amount of reverb desired. The reverb signal is mix-
ed into the delay line by rotating the reverb control
clockwise until adequate reverb is obtained. Remember
that the master reverb control must be turned up before
individual reverb takes effect.
3. The bass control determines the low frequency
response of the individual channel. The 120 PA bass
control is a type of electronic crossover which acts as a
volume control for the low frequencies. Because of the
design of this control, it is possible to obtain both bass
boost and cut. The vertical position (between 5 and 6)
will yield a flat response. Clockwise operation results in
a boost and counter-clockwise operation results in a
cut
4. The treble control determines the high frequency
response of the individual channel. The treble control is
part of an electronic crossover and functions as a
volume control for the high frequencies. The vertical
position (between 5 and 6) yields flat response, while
clockwise settings boost highs and counter-clockwise
settings yields a treble cut.
5. The input jacks are designed to accept a high
impedance microphone or instrument.
MASTER SECTION
Field
experience
has
proven
that
a
professional
PA
mix-
er/amplifier
must
be
equipped
with
a
full
set
of
master
controls.
While
the
bass,
treble,
and
reverb
controls
enable
good
tonal
mix
in
the
individual
channels,
it
is
difficult
to
obtain
a
good
overall
balance
unless
the
master
controls
are
present
6.
The
master
reverb
is
the
control
that
determines
how
much
of
the
delayed
(reverb)
signal
is blended
back
into
the
master
mixer.
The
master
reverb
is
a
return
level
control
and
must
be
turned
up
before
any
reverb
effect
is
heard
at
the
output.
The
master
reverb
level
should
be
set
so
that
the
individual
reverb
send
controls
on
each
of
the
channels
have
adequate
control
variation.
7.
The
master
volume
control
controls
the
gain
of
the
master
mixer
by
use
of
variable
negative
feedback
The
use
of
active
mixing
allows
your
120
PA
Mix-
er/Amplifier
to
perform
as
well
as
many
studio
mixing
consoles.
This
method
is
the
same
used
on
the
latest
recording
mixers
and
yields
the
lowest
distortion
and
noise
than
any
other
method.
The
master
volume
sets
the
level
for
the
entire
system.
The
master
volume
should
be
set
approximately
in
the
middle
position
(4-
6),
and
fine
adjustment
in
volume
should
be
made
with
the
individual
controls
on
each
channel.
8.
The
reverb
footswitch
jack
provides
a
method
for
reverb
cut
off
by
use
of
the
optional
remote
footswitch.
Any
footswitch
with
the
proper
plug
(stan-
dard
phone
plug)
and
a
shielded
cable
will
work
with
this
jack
9.
The
pilot
light
indicates
when
power
is
applied
to
the
amplifier
10.
The
three
wire
line
cord
has
been
provided
for
your
protection
and
should
be
connected
to
the
proper
line
voltage
as
indicated
on
the
back
panel.
DO
NOT
REMOVE
GROUND
PIN
ON
PLUG.
11.
The
fuse
is
located
within
the
cap
of
the
fuse
holder
and
should
be
replaced
with
one
of
the
proper
value
if
it
should
fail.
It
is
necessary
that
the
proper
value
fuse
be
used
to
avoid
damage
to
the
equipment
and
to
avoid
voiding
the
warranty.
Models
that
have
circuit
breakers
can
be
reset
by
depressing
the red
button.
If
the
breaker
trips
repeatedly,
take
the
unit
to
a
qualified
service
center
for
inspection.
12.
The
line
power
switch
is
of
the
three
position
type
with
the
center
position
being
off.
The
three
posi-
tion
switch
has
two
on
positions
which
are
used
to
ground
the
amplifier
properly.
One
of
the
on
positions
will
yield
the
least
hum
or
popping
when
the
microphone
is
touched
and
this
is
the
position
that
should
be
used.
13.
The
speaker
output
jacks
are
designed
to
be
used
with
a
total
load
of
FOUR
OHMS.
Speaker
systems
of
higher
impedance
can
be
used
with
a
slight
loss
in
output
power.
Speaker
systems
with less
than
a
total
of
four
ohms
can
be
used
with
the
risk
of
overloading
the
power
amplifier.
Slightly
less
power
will
be
delivered
to
lower
impedances
because
of
the
uni-
que
limiting
action
of
our
integral
protection
system.
The

power amplifier is built on a large aluminum heatsink to
cool the output devices. A thermostat is connected to
this heatsink to shut the system down in case of
overheating. Low speaker impedances tend to cause
the amp to run hotter than normal, and could cause the
automatic cutoff to operate if the output stage becomes
hot enough to endanger the output devices. The ther-
mostat is self re-setting and normal operation will be
restored when the unit reaches safe operating
temperatures. If thermal shutdown is apparent then you
are overloading the system and continued use in this
manner will damage the system. Never use less than a 4
ohm total load on the 120 module. The output voltage
available from this unit is approximately 22 VRMS into 8
ohms with proper line input.
14. The large line cord retainers on the rear panel
are provided for your convenience in storing the AC line
cord during transport of the unit.