Peavey Mark III Bass User manual

MARKIISERES
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OPERATING GUIDE
GENERAL DESCRIPTION
The
Peavey
Mark
III
Bass
amp
is
the
result
of
many
years
of
field
experience,
combined
with
the
latest
electronic
circuitry
to
produce
what
we
believe
is
the
finest
bass
amp
on
the
market
today.
The
new
Bass
utilizes
newly
engineered
circuitry
from
input
to
output,
greatly
increased
dynamic
range.
equalization
(passive
and
active),
coupled
with
a
six-band
graphic
equalizer,
pre
and
post
gain
controls,
built-in
variable
electronic
crossover,
“DDT”
compression
circuitry.
AUTOMIX,
and
complete
patch
panel
capability.
Our
engineers
have
"brought
it
all
together”
in
this
one
compact
and
powerful
unit
that
represents
the
ultimate
in
contemporary
electronic
design
and
packaging
in
musical
instrument
amplifiers.
The
new
Bass
is
powered
by
our
totally
new
400B
power
module
which
utilizes
eight
high
voltage
ultra-fast
output
devices
bolted
to
a
massive
aluminum
heatsink.
The
400B
module
incorporates
Peavey’s
unique
"DDT”
(Distortion
Detection
Technique)
compression
circuit
that
senses
the
onset
of
clipping
and
electronically
compresses
the
signal
to
avoid
overload
of
the
power
amplifier,
thus
producing
the
tightest
and
cleanest
mono
bass
sound
possible
while
minimizing
the
danger
of
speaker
blowout
at
high
output
levels.
This
unique
compressor
has
specially
computed
attack
and
releasetimes
tailored
to
retain
the
dynamics
of
stringed
instruments.
An
entirely
new
series
of
color-coded
knobs
have
been
designed
for
this
and
other
Mark
{Ii
amplifiers
that
not
only
provide
easy
function
identification
by
color,
but
also
feature
greatly
improved
visibility
and
“touch
indexing”
capability.
To
provide
even
greater
flexibility,
Peavey
has
designed
one
channel
with
active
EQ
and
parametric
middle,
while
the
other
channel
uses
the
latest
in
passive
equalization.
Our
built-in
variable
electronic
crossover
is
unique
in
its
capability
to
electronically
set
the
crossover
at
any
point
between
50
and
500
Hz,
thus
allowing
bi-amplification
of
the
bass
system
when
utilized
with
an
external
power
amplifier
/speaker
combination.
It
is
generally
recognized
that
bi-amping
a
bass
produces
the
loudest
and
most
satisfactory
results
obtainable
with
this
instrument.
The
comprehensive
patch
panel
featuring
both
input
and
output
connectors
enables
the
Bass
to
be
used
with
almost
any
accessory.
even
those
requiring
600-Ohm
impedances.
The
six-band
graphic
equalizer
is
switch
programmable
into
either
or
both
channels
which
are,
in
turn,
controlled
by
our
AUTOMIX
remote
footswitch.
AUTOMIX
enables
the
user
to
select
either
or
both
channels
and
LED's
indicate
which
channeis
are
active
in
the
AUTOMIX
mode.
Our
unique
pre
and
post
gain
controls
make
possible
total
control
of
level
and
overall
dynamics
from
each
channel,
making
the
AUTOMIX
feature
even
more
versatile.
Overall,
the
Mark
III
Bass
is
one
of
the
most
electronically
sophisticated
instrument
amplifiers
ever
made
and,
in
total,
represents
a
quantam
jump
in
instrument
amplifier
technology.
WARNING: To prevent electrical shock or fire hazard, do not expose this
appliance to rain or moisture.

BASS
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DIAGRAM
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PRE
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AMP
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AMP
2
LINE
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AUTOMIX
COMPENSATION
AUTOMIX
CIRCUITRY
REMOTE
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PREAMP
SWITCH
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OUT
AMP
POWER
AMP
IN
POWER
AMP
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SPKR
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PREAMP
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POST
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COMPRESSION
A
LED
FRONT PANEL
INPUT JACKS 1 AND 2
The
Bass
features
both
a
high
gain
(1)
and
a
low
gain
(2)
(-6
dB)
input
to
enable
it
to
accept
signals
of
varying
levels
and
also
to
facilitate
using
two
instruments
into
either
channel.
The
high
gain
(1)
input
is
the
one
normally
used.
If
the
output
signal
from
your
instrument
or
its
associated
electronics
is
overloading
the
high
gain
(1)
input,
then
the
low
gain
(2)
input
should
be
used.
Because
of
the
unique
switching
Circuitry,
1
and
2
inputs
automatically
are
gain
balanced
when
two
instruments
are
inserted
into
both
inputs
The
Bass
AUTOMIX
function
has
been
recently
redesigned
around
the
latest
in
analog
switching
circuitry
and
includes
LED
activity
indicators
to
indicate
the
channels
in
use.
(PLEASE
NOTE:
CHANNEL
LED'S
ARE
INACTIVE
UNTIL
AN
INSTRUMENT
IS
PLUGGED
INFO
THE
AUTOMIX
JACK.)
NOTE!
THE
AUTOMIX
JACK
IS
A
SPECIAL
SWITCHING
JACK
THAT
HAS
A
DOUBLE
DETENT;
I.E.,
TWO
POSITIONS.
TO
ACHIEVE
PROPER
OPERATION,
THE
INPUT
PLUG
MUST
BE
INSERTED
ALL
THE
WAY,
OR,
TO
THE
SECOND
CLICK.
PROPER
INSERTION
OF
THE
INSTRUMENT'S
INPUT
PLUG
WILL
BE
INDICATED
BY
ILLUMINATION
OF
EITHER
OR
BOTH
AUTOMIX
LED
ACTIVE
CHANNEL
INDICATORS.
AUTOMIX JACK (3)
The
AUTOMIX
circuitry
was
pioneered
by
Peavey
several
years
ago
in
order
to
enable
the
use
of
both
channels
of
the
amplifier.
It
used
to
be
common
to
play
through
one
channel
only
while
the
other
channel
was
not
used.
Our
AUTOMIX
circuitry
enables
the
player
to
utilize
the
full
capability
of
this
amplifier
by
allowing
either
or
both
channels
to
be
used
during
a
performance.
The
switching
function
is
controlled
by
the
remote
footswitch
which
is
supplied
as
standard
equipment
with
the
amplifier.
The
AUTOMIX
effect
is
activated
when
your
input
plug
is
fully
inserted
into
the
AUTOMIX
jack
and
is
accompanied
by
illumination
of
one
or
both
LED's.
Our
improved
circuitry
has
provided
post
gain
controls
for
both
channels,
which
are
actually
master
volume
controls
for the
respective
channels.
enabling
sensitivity
and
dynamics
to
be
independently
adjusted
in
each
channel
with
the
selection
of
either
or
both
channels
accomplished
by
the
AUTOMIX
circuitry
and
its
remote
footswitch.
The
remote
footswitch
features
a
“Selector”
button,
which
enables
alternate
selection
of
either
Channel
A
or
Channel
B.
The
“Combiner”
button
operates
to
mix
the
two
channels
together
and
defeats
the
“Selector”
button.
Obviously,
when
the
"Combiner"
button
is
activated.
both
channels
are
in
the
circuit
as
indicated
by
their
LED
indicators.
When
in
the
combined
mode,
the
"Selector"
button
Is
inoperative
since
the
combined
mode
must
functionally
override
the
select
mode
to
operate
both
channels
simultaneously.
To
reactivate
the
select
mode.
depress
the
“Combiner”
button
once.
PRE GAIN (4)
The
pre
gain
controls
determine
the
amount
of
gain
produced
in
the
input
preamp.
Please
understand
that
this
control
determines
the
sensitivity
and
not
the
power
output
of
the
amplifier.
The
control
settings
in
no
way
can
be
related
to
the
power
the
amp
Is
delivering
to
the
speakers
because
of
a
number
of
other
factors
such
as
the
input
signal
amplitude,
setting
of
the
post
gain
controls,
etc.
EQUALIZATION
The
equalization
circuitry
of
the
Bass
is
extremely
versatile,
as
well
as
reasonably
simple
to
operate.
Channel
B
features
the
latest
active
circuitry.
while
Channel
A
is
designed
around
somewhat
conventional
passive
Circuitry.
Because
we
have
included
parametric
middle
equalization.
some
knowledge
and
operating
experience
is
necessary
to
obtain
maximum
benefit
from
this
versatile
feature.
CHANNEL
A
EQUALIZATION
LOW EQUALIZATION CONTROL (5)
The
low
equalization
control
determines
the
low
frequency
emphasis
and
is
capable
of
substantially
more
effect
than
many
of
the
more
conventional
passive
tonal
networks.
For
this
reason,
the
contro!
will
tend
to
make
the
amp
sound
"bassy”
at
high
settings.
We
have
designed
the
circuitry
to
provide
more
tonal
variation
to
allow
you
a
greater
range
of
variable
tonalities.
MIDDLE EQUALIZATION CONTROL (6)
The
middle
equalization
control
is
used
to
tailor
the
relative
levels
of
the
vital
mid
range
frequencies.
Experimentation
with
this
middle
control
will
show
that
it
is
very
effective
and
enables
the
“voicing”
of
Channel
A
to
be
changed
significantly
because
of
its
advanced
circuit
desiqn.

FRONT PANEL DIAGRAM
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HIGH EQUALIZATION CONTROL (7)
The
high
equalization
comro!
sets
the
amount
of
high
end
boost
available
and
its
effect
is
dramatic.
Overboosting
of
the
highs
Is
generally
not
desirable
since
it
tends
to
cause
a
strident
sound,
as
well
as
tending
to
emphasize
residual
preamp
noise.
Our
equalization
circuit
is
very
effective
and
experimentation
will
allow
the
user
to
achieve
almost
any
tonal
coloring
desired.
CHANNEL B EQUALIZATION
LOW ACTIVE EQUALIZATION CONTROL (8)
The
low
equalization
contro!
is
of
the
active
shelving
type
capable
of
producing
either
a
boost
or
a
cut
of
the
low
frequencies.
Vertical
(straight
up
or
12:00
o'clock)
settings
produce
a
flat
response.
while
counter-clockwise
settings
produce
a
cut,
and
clockwise
settings
produce
a
boost.
It
should
be
noted
that
because
this
circuit
is
active.
significant
amounts
of
boost
are
available.
One
should
avoid
overboosting
the
lows
since
this
will
tend
to
require
excessive
amounts
of
power
trom
the
amplifier
and
might
tend
to
cause
excessive
compression
or
overdrive
the
power
amp
if
compression
is
switched
out
at
high
boost
(clockwise)
settings.
"PARAMID” MIDDLE EQUALIZATION
Our
PARAMID
equalizer
is
capable
of
two
distinct
equalization
functions:
(1)
it
features
the
ability
to
vary
the
center
frequency
of
its
action
over
a
considerable
range:
(2)
A
second
control
determines
whether
the
selected
frequencies
are
cither
boosted
or
cut
and
by
how
much.
PARAMID
CONTROL
(9):
The
PARAMID
control
operates
very
similar
to
the
low
and
high
equalization
controls
since
in
the
vertical
(straight
up
or
12:00
o'clock)
position,
no
effect
is
produced,
while
counter-clockwise
settings
produce
a
cutting
effect
or
notch
and
clockwise
se‘tirgs
produce
a
boosting
effect
or
peak.
Care
should
be
taken
not
to
overboost
since
this
effectively
increases
the
gain
at
the
selected
frequencies
and
could
overdrive
the
power
amp
and/or
speaker.
as
well
as
increase
the
residual
noise.
SHIFT
CONTROL
(10):
This
control
determines
the
center
frequency
of
the
peak
or
notch.
HIGH ACTIVE EQUALIZATION CONTROL (11)
The
Channel
B
high
equalization
control
is
of
the
active
shelving
type,
capable
of
producing
either
a
boost
or
cut
of
the
high
frequencies.
Its
operation
is
similar
to
the
low
and
PARAMID
controls
in
that
a
vertical
(straight
up
or
12:00
o'clock)
position
produces
a
flat
response.
while
counter-clockwise
positions
yield
cut
and
clockwise
settings
yield
boost.
It’s
a
good
Idea
to
avoid
extreme
boosting
of
high
frequencies
since
this
tends
to
make
the
amp
sound
strident
and
unduly
emphasize
string
noises,
etc.
POST GAIN CONTROLS (12)
The
post
gain
controls
are
the
“master
gain”
controls
for
the
respective
channels.
The
action
of
these
controls
is
conventional
and
experimentation
will
illustrate
their
function.
Please
be
aware
that
extremcly
low
settings
of
the
post
gain
controls
will
require
extremely
high
settings
of
the
pre
gain
controls
with
subsequent
loss
of
dynamic
range
in
the
input
preamp.
This
may
be
desirable
in
some
situations
to
create
distortion
effects
in
the
input
circuitry.
However,
with
bass
instruments,
it’s
generally
desirable
to
maximize
dynamic
range
inthe
input
preamp
because
of
the
strong
output
signals
generated
by
most
bass
instruments.
This
is
very
important
for
maximum
compression
capability
without
distortion.
Therefore.
we
recommend
post
gain
settings
of
"7"
or
higher
for
normal
use.
CROSSOVER (13)
The
built-in
electronic
crossover
is
designed
tc
allow
bi-amping
and
has
the
capability
to
allow
setting
the
crossover
frequency
at
any
point
between
50
and
500
Hz.
The
reason
we
have
included
a
variable
crossover
is
to
allow
matching
of
various
types
of
speaker
enclosures
together:
i.e.
one
18"
ina
folded
horn
and
two
12"
direct
radiators
would
need
to
be
crossed
over
differently
than
one
15”
folded
horn
and
two
10”
direct
radiator
speakers.
Our
frequency
variable
system
allows
total
flexibility.
The
outputs
cf
the
crossover
located
on
the
patch
panel
are
600
Ohms
output
impedance
and
are
capable
of
greater
than
2
Volts
RMS
output.
The
built-in
power
amplifier
of
the
Bass
which
normally
is
internally
connected
full
range
may
be
patched
(using
a
short
shielded
cord)
into
either
the
low
or
the
high
output
of
the
crossover
network.
thus
using
the
internal
power
amp
as
one-half
of
the
bi-amp
drive
system.
The
output
cf
both
channels
plus
the
graphic
equalizer
(when
switched
in)
feeds
into
the
electronic
crossover
in
order
to
be
sure
that
all
systems
are
operative
in
the
bi-amp
mode.
Experimentaton
with
the
actual
amp/speaker
combinations
will
illustrate
the
best
setting
of
the
crossover
frequency
control.
One
shauld
remember
that
the
internal
compressor
will
operate
only
on
the
internal
amplifier
in
the
bi-amp
mode.
The
electronic
crossover
can
be
used
as
a
low
cut
filter
when
conditions
require
strong
penetration
without
overload.
This
is
often
desirable
at
outside
concerts.
Remova!
of
the
extreme
low
end
response
maximizes
headroom
and
makes
the
Bass
amp
sound
louder.
Simply
patch
the
internal
power
amp
to
the
Bi-Amp
High
Out
and
adjust
the
frecuency
to
ihe
desired
rolloff
point.
GRAPHIC EQ ASSIGN SWITCH (14)
The
graphic
EQ
assign
switch
on
each
channel
allows
“pre-programming”
either
or
both
channels
to
either
go
through
or
to
bypass
the
graphic
equalizer.
This
switching
assign
capability
allows
the
operator
to
run
one
channel
through
the
graphic
while
bypassing
the
other
or
to
run
both
channels
into
or
around
the
graphic.
This
assign
capability
takes
on
even
greater
importance
when
ublizing
the
AUTOMIX
function
since
a
tremendous
range
of
variation
can
be
obtained
between
the
channels
when
one
channel
is
bypassing
the
graphic
while
the
other
is
fed
into
it.

"DDT" COMPRESSION LED AND SWITCH (15) (16)
The
Bass
is
a
compact
and
powerful
amplifier
that
features
a
210-Watt
RMS
power
amplifier
with
a
full
complement
of
equalization
controls
and
a
new
type
of
dynamic
compression.
The
compression
effect
enables
us
to
maximize
the
performance
of
the
amp
‘speaker
Combination.
We
have
determined
through
much
research
that
the
compression
circuitry
should
prevent
the
power
amp/speaker
combination
trom
running
out
of
headroom
(clipping)
and
should
be
as
simple
to
operate
as
possible
to
avoid
undue
complication
for
the
user.
Our
compression
circuit
is
very
effective
and
is
controlled
by
a
simple
on/off
switch
(16).
Because
of
the
dynamics
and
the
percussive
nature
of
plucked
strings.
it
is
quite
common
to
activate
the
compression,
as
indicated
by
the
limit
LED
(light
emitting
diode}
(15)
at
reasonably
low
output
levels.
One
should
not
be
concerned
that
the
limit
LED
indicated
compression
virtually
constantly
during
a
performance
since
this
is
what
it
was
designed
to
do:
ie..
to
maximize
the
dynamics
available
from
the
amp
within
its
power
output
capabilities.
The
compression
effect
may
be
switched
off
by
the
toggle
switch
on
the
front
panel.
We
have
not
included
other
compression
controls
since
we
have
designed
an
exclusive
“Distortion
Detection
Technique’
circuit
that
senses
conditions
that
might
cause
overload.
and
compression
is
activated
only
when
clipping
is
imminent.
This
technique
effectively
utilizes
every
precious
Watt
available
from
the
power
amplifier.
GRAPHIC EQUALIZER (17)
The
Bass
features
a
very
effective
six-band
active
EQ
circuit.
Each
band
has
been
carefully
selected
for
the
proper
frequency
points,
combining
characteristics.
and
precise
bandwidth
(“Q”)
to
most
effectively
handle
the
spectrum
covered
by
bass
instruments.
This sophisticated equalization system has been created using the latest computer-aided design techniques and has resulted ina
Circuit
that
is
not
only
exceptional
in
performance,
but
provides
remarkable
consistency
across
its
frequency
range.
This
equalizer
is
capable of a 30 dB range: ie.. 15 dB boost or 15 dB cut in each of the six bands.
Each
channel
ot
the
Bass
has
an
assign
switch
(14)
that
allows
the
signal
from
the
respective
preamps
to
be
sent
either
directly
to
the
power
amplifier
or
through
the
graphic.
When
this
assign
switch
is
in
the
“up”
or
“in”
position.
its
signal
Is
routed
through
the
graphic:
and
when
it's
in
the
“down”
or
“out”
position.
that
channel's
signal
is
routed
directly
to
the
power
amp.
The
action
of
a
graphic
equalizer
is
generally
well
understood
but
several
precautions
should
be
taken
to
avoid
overboosting
the
frequency
extremes
and
thus
creating
difficulties.
The
graphic
equalizer
follows
the
channel
equalization
which
is
substantial
by
itself
and
when
combined
with
the
boost
capability
of
the
graphic,
the
range
becomes
tremendous.
When
running
the
individual
channel
low,
mid
or
high
boost
near
full
clockwise
positions.
one
should
generally
avoid
overboosting
that
particular
range
again
in
the
graphic.
This
“double
EQ”
Capability
enables
a
fantastic
amount
of
cut
ot
boost
but
must
be
used
wisely
to
avoid
creating
a
“boomy”
or
“muffled”
sound
when
too
much
low
end
is
boosted.
as
well
as
creating
“strident”.
“screechy”
or
noisy
operation
when
too
much
high
end
is
boosted.
One
should
also
be
aware
that
the
“double
equalization”
available
in
the
Bass
also
may
cause
problems
in
the
extreme
Cut
positions
since
Cutting
the
EQ
is
the
equivalent
of
reducing
the
gain
for
the
affected
frequency
range.
Experimentation
will
quickly
illustrate
the
effectiveness
of
these
equalization
controls
and
generally.
no
difficulty
whatsoever
should
be
encountered.
PATCH PANEL
A
full
patch
panel
has
been
included
to
enable
patching
effects
devices
“in
line”
and
also
to
provide
a
frequency
compensated
low
impedance
output
to
drive
recording
or
P.A.
consoles
directly
without
need
of
a
“direct
box”
or
other
amp/mixer
interface
device.
PREAMP
OUT
(18)/POWER
AMP
IN
(19)
10
allow
“in
line”
patching
of
the
various
accessories.
we
have
included
a
system
of
preamp
out/power
amp
in
jacks
on
the
front
panel.
The
preamp
out
is
the
straight
preamp
signal
which
is
the
sum
of
the
outputs
of
the
two
channels.
The
output
level
iS
approximately
2
Volts
RMS
and
is
a
relatively
low
(600
Ohms)
output
impedance.
The
preamp
out
signal
is
connected
through
a
switching
contact
to
the
power
amp
input
jack
and
normally
the
preamp
out
is
internally
connected
to
the
power
amp's
input.
This
circuit
allows
basically
two
modes
of
operation.
When
signal
is
taken
from
the
preamp
output.
signal
is
also
delivered
to
the
internal
power
amplifier.
If
access
to
the
internal
power
amplifier
is
needed
or
if
some
accessory
device
such
as
a
noise
gate.
delay
line.
effects
device,
etc..
Is
tobe
patched
“in
line”,
then
the
preamp
output
signal
must
be
connected
to
the
auxiliary
unit's
input,
while
the
auxiliary
unit's
output
must
be
connected
to
the
power
amp
input
with
shielded
cables.
thereby
placing
the
auxiliary
unit
in
series
or
"in
line”
with
the
normal
signal
path.
Additional
booster
amp
/speaker
combinations
should
be
patched
using
the
preamp
output.
With
this
unique
patching
facility,
many
interesting
effects
can
be
accomplished.
LINE OUT (20)
Many
attempts
have
been
made
over
the
years
to
patch
the
preamp
circultry
of
musical
instrument
amptifiers
directly
into
recording
or
sound
reinforcement
mixing
consoles
Most
of
these
attempts
have
been
unsuccessful
and
have
resulted
in
players
and
soundmen
having
to
utilize
various
forms
of
what
is
popularly
referred
to
as
a
“direct
box"
which,
of
course,
means
further
complication,
expense,
etc.
Most
previous
attempts
at
patching
signals
out
of
musical
instrument
amplifiers
have
ignored
a
very
basic
fact...generally
poor
frequency
response
from
the
musical
instrument
amplifiers
speaker
system.
Most
amp
manufacturers
have
compensated
for
the
speaker's
poor
top
end
frequency
response
by
building
in
some
degree
of
high
frequency
boost
in
order
to
satisfy
the
player.
While
this
built-in
high
frequency
boost
is
indeed
good
for
increasing
the
response
from
the
system.
it
tends
to
cause
excessive
residual
noise.
as
well
as
“strident”
or
“screechy”
tonality
in
the
direct
preamp
output
signal.
Our
line
output
has
a
built-in
compensation
circuit
that
very
closely
matches
the
rolloff
characteristic
of
a
speaker
system
in
order
to
produce
an
output
signal
that
corresponds
very
closely
to
what's
being
heard
from
the
speaker
system.
There
is
also
a
rolloff
of
the
extreme
low
frequencies
to
avoid
overload
of
the
associated
console
by
the
“sub”
bass
signals.
This
very
inportant
feature
should
prove
very
helpful
in
eliminating
the
need
for
direct
boxes
and
micing
of
musical
instrument
amplifiers.
The
signals
from
the
line
output
jacks
are
low
impedance
(600
Ohms)
unbalanced
at
a
signal
level
of
2
Volts
RMS
BI-AMP
LOW
OUT
(21)
The
Bi-Amp
Low
Out
is
the
output
of
the
crossover
network
passing
the
low
frequency
signals
from
the
selected
crossover
point
down.
Frequencies
above
this
point
are
attenuated
12
dB
per
octave.
The
output
level
is
greater
that
2
Volts
at
600
Ohms
impedance.
BI-AMP
HIGH
OUT
(22)
The
Bi-Amp
High
Out
is
the
output
of
the
crossover
network
passing
the
high
frequency
signals
from
the
selected
crossover
point
up.
Frequencies
below
this
point
are
attenuated
12
dB
per
octave.
The
output
level
is
greater
than
2
Volts
at
600
Ohms
impedance.
BI-AMPING
The
purpose
of
bi-amping
is
to
eliminate
various
kinds
of
distortion
by
maximizing
the
system's
overall
dynamic
range
by
utilizing
separate
independent
power
amps
to
amplify
the
low
and
the
high
frequencies.
In
systems
where
the
various
components
are
known
such
as
particular
speakers
in
particular
enclosures,
it
has
been
common
practice
to
preset
the
crossover
point
in
order
to
achieve
optimum
balance.
In
musical
instrument
amplifiers
that
are
used
with
a
wide
variety
of
different
speaker
systems
operated
in
different
sized
areas,
we
felt
it
was
necessary
to
incorporate
a
variable
electronic
crossover
to
facilitate
matching
different
amp
/speaker
combinations
together
into
a
compatible
system.
Typically.
the
internal
amplifier
is
used
as
one
channel
of
the
bi-amp,
while
another
external
amplifier
is
used
as
the
other.
As
a
general
rule.
the
most
powerful
of
the
two
amps
required
should
be
used
for
the
low
frequency
since
this
end
of
the
spectrum
generally
demands
more
power
output
than
the
high
end
of
the
spectrum:
Le..
if
you
have
an
external
400-Watt
power
amplifier.
you
should
use
the
internal
200-Watt
power
amplifier
as
the
high
end
of
the
system
by
utilizing
a
small
patch
cord
and
patching
from
high
out
to
power
amp
in.
The
low
out
should
then
be
patched
to
the
input
of
the
external
400-Watt
power
amplifier.
with
the
speaker
for
the
high
end
being
patched
into
the
out
jacks
of
the
internal
power
amplifier
and
the
low
frequency
speakers
patched
into
the
external
amp’s
outputs.
The
external
amp
should
be
gain
matched
using
its
level
control
to
set
a
proper
balance”
of
highs
and
lows
to
compensate
for
different
speaker
efficiencies
and
power
amp
sensitivities.
The
proper
crossover
frequency
point
should
then
be
determined
by
experimentation,
using
various
crossover
frequency
settings
after
the
desired
channel
gain
and
equalization
has
been
set
in
the
preamp.
Obviously,
if
an
external
power
amplifier
with
less
than
200
Watts
is
used,
it
should
be
used
for
the
high
end.

CAUTION
IT
IS
GENERALLY
NOT
ADVISABLE
TO
USE
HIGH
FREQUENCY
HORN/DRIVER
COMBINATIONS
SUCH
AS
USED
IN
SOUND
REINFORCEMENT
SYSTEMS
AS
THE
TOP
END
OF
ABASS
GUITAR
SYSTEM.
THE
UPPER
HARMONICS
OF
BASS
INSTRUMENTS
ARE
BETTER
HANDLED
BY
CONE
TYPE
RADIATORS
WHICH
WILL
SOUND
SMOOTHER
AND
WILL
HANDLE
MORE
POWER
THAN
HORN/DRIVER
COMBINATIONS.
PILOT LED (23)
The
pilot
LED
indicates
when
the
electrical
supply
is
switched
on
and
ıs
actually
delivering
power
to
the
amplifier.
AUTOMIX
REMOTE
SWITCH
SOCKET
(24)
The
remote
switch
socket
is
the
standard
"DIN"
type
and
serves
as
the
amp
connection
for
tne
supplied
remote
footswitch.
Please
note
that
the
"DIN”
plug
has
an
indentation
that
must
be
matched
with
the
matching
indentation
in
the
footswitch
receptacle
on
the
front
panel.
This
keying
action
allows
the
footswitch
to
be
connected
only
in
the
proper
manner.
if
the
plug
is
forced
or
undue
pressure
is
exerted
on
the
shell
or
pins,
damage
could
result
to
the
footswitch
plug
or
the
chassis
mounted
socket.
As
with
any
precision
device,
reasonable
care
should
be
exercised.
FUSE (25)
The
fuse
is
located
within
the
cap
of
the
fuseholder
and
must
be
replaced
with
one
of
the
proper
type
and
value
if
it
should
fail.
It's
necessary
that
the
proper
type
and
value
fuse
be
used
in
order
to
avoid
damage
to
the
equioment
and
to
prevent
voiding
ihe
warranty.
If
your
unit
repeatedly
blows
fuses,
it
should
be
taken
to
a
qualified
service
center
for
repair.
POWER SWITCH (26)
On
domestic
units.
the
power
switch
is
of
the
three-position
type
with
the
center
position
being
“OFF”
This
switch
has
two
"ON"
positions,
one
of
which
is
used
to
ground
the
amplifier
properly.
One
of
the
“ON”
positions
will
yield
the
lowest
amount
of
residual
hum
or
"popping”
when
the
instrument
is
touched
and
this
is
the
position
that
should
be
used
On
export
models,
we
utilize
a
simple
on/off
switch
that
does
not
have
multiple
“ON”
positions
since
the
grounding
(earthing)
conditions
vary
with
the
different
electrical
systems
of
the
United
States
versus
other
nations.
LINE CORD (27)
For
your
safety.
we
have
incorporated
a
three-wire
line
(mains)
cable
with
proper
grounding
facilities.
It
is
not
advisable
to
remove
the
ground
pin
under
any
circumstances.
If
it
is
necessary
to
use
the
amp
without
proper
grounding
facilities.
suitable
grounding
adaptors
should
be
used.
Much
less
noise
and
greatly
reduced
shock
hazard
exists
when
the
unit
is
operated
with
the
proper
grounded
receptacles
SPEAKER
OUTPUTS
(28)
The
speaker
output
jacks
are
wired
in
parallel
and
are
of
the
standard
'4"
type.
Either
or
both
may
be
used
when
connecting
your
speaker
system.
The
new
400B
power
module
has
been
designed
to
work
with
a
wide
range
of
speaker
impedances.
This
module
Is
designed
for
optimum
performance
into
a
4-Ohm
load
but
will
easily
handle
lower
(2-Ohm)
and
higher
(8-Ohm)
loads.
One
should
be
aware
that
a
higher
than
4-Ohm
load
wil!
result
in
somewhat
less
power.
Operating
this
unit
into
2
Ohms
is
acceptable
if
proper
ventilation
IS
provided.
UNDER
NO
CONDITIONS
SHOULD
THE
BACK
MOUNTED
HEATSINK
OR
THE
COOLING
GRILLE
ON
TOP
OF
THE
AMP
BE
BLOCKED
OFF
OR
OBSTRUCTED
DURING
OPERATION.
When
operating
at
below
2
Ohms.
the
internal
voltage
‘current
limiting
circuit
wil
limit
the
dissipation
of
the
output
devices
and
continuous
operation
in
this
overload
condition
will
activate
the
automatic
thermal
protective
circuitry.
This
thermostatically
controlled
thermal
protective
circuitry
is
automatically
resetting
and
will
reactivate
as
soon
as
the
junctions
of
the
silicon
output
devices
again
reach
safe
operaling
temperatures.
Because
of
the
unique
design
of
the
DDT
compressor.
the
circuitry
will
still
minimize
clipping
regardiess
ofload
values.
LINE (MAINS) CORD RETAINER (29)
We
have
provided
two
large
molded
line
cord
retainers
on
the
rear
panel
to
allow
storage
of
the
mains
cable
for
travel.
In
operation
the
cable
should
be
completely
unwrapped
to
allow
maximum
heat
dissipation
from
the
rear
panel
/
heatsink.
REAR PANEL DIAGRAM
BASS SPECIFICATIONS
OUTPUT
POWER:
INPUT
IMPEDANCE:
210
watts
RMS
@
1%
THD
into
4
ohms
220
K
ohms
300
watts
RMS
@
1%
THD
into
2
ohms
SIGNAL-TO-NOISE
RATIO:
SENSITIVITY:
70
dB
(50
K
ohms
source
impedance)
15 mV @ 1 KHz
(Tone
Controls
Flat,
Volume
12:00)

EXAMPLE OF BI-AMP HOOKUP
Set crossover point for most pleasing “Blend”
and freedom from speaker distortion,
(a
@
E o
Balance system with external power amo's
Gain Control.
x
To external amp's
speaker output
|
a
High Frequency System Low Frequency System
215 BW 118FH
4 Ohms 4 Ohms
PEAVEY
ELECTRONICS
CORP
Post Office Box 2898 Meridian, MS 39301
Telephone: [phone]
“Specifications are subject to change without notice.”
PRINTED IN U.S.A.
80301002 € 1979