Sherwood XA-5450 User manual

OPERATION
MANUAL
a
G Sherwood
XA-5450
BRIDGEABLE
2
CHANNEL
AMPLIFIER

Congratulations
on
your
rurcnase
:
Your
new
high
fidelity
bridgeable/stereo
amplifier
is
designed
to
deliver
maximum
enjoyment
and
years
of
trouble
free
service.
Please
take
a
few
moments
to
read
this
manual
thoroughly.
It
will
explain
the
features
and
operation
of
your
unit
and
help
insure
trouble
free
installation.
Features
© Tri-power
© Bridgeable/mono
Two ohm stable per channel
© Gold plated screw terminals
© Variable Bass EQ from +0 dB to 6 dB gain at
45 hertz
@ Low/line level input
© Gold plated RCA jacks
@ Electronic high pass crossover
@ Electronic low pass crossover
@ Mos-fet power supply
@ Anti-thump circuit
Power LED
@ Peak LED
@ Plug in fuse
@ Built-in cooling fan
3
PrIiCcuUaUUVLIs. NvTaAU rinse:
® |f after reading the directions you feel uncomfortable
about
installing
the
amplifier
in
your
car,
or
not
equipped
or
competent
to
do
so,
you
should
have
the
amplifier installed by an authorized Sherwood
Dealer/Installer. It's your car !
®
Negative
battery
terminal
must
be
disconnected
before
any
electrical
connections
are
made.
®
Be
sure
to
choose
a
location
that
provides
substantial
ventilation
for
the
amplifier.
The
most
preferred
locations
would
be
in
your
car's
trunk,
under
the
front
seats
or
on
the
back
wall
of
a
truck.
®
The
location
chosen
should
provide
at
least
2"
of
clearance
above
the
amplifier
for
adequate
ventilation.
®
If
the
amplifier
is
to
be
mounted
vertically,
be
sure
that
it
is
in
a
place
where
adequate
air
will
flow
along
the
length
of
its
heatsink
fins
for
cooling.
®
NEVER
mount
the
amplifier
up
side
down,
this
will
cause
the
heat
to
rise
back
into
the
amplifier
causing
thermal
shutdown
or
possible
permanent
damage.
®
NEVER
mount
the
amplifier
in
a
location
that
is
subject
to
direct
sunlight
or
exposed
to
moisture.
®
Be
sure
to
mount
the
amplifier
to
a
strong,
solid
surface
which
will
not
give
way
under
the
stress
of
a
sudden
stop
or
accident.
®
Make
sure
that
the
mounting
screws
will
not
penetrate
the
gas
tank,
brake
and
fuel
lines,
wiring
or
other
critical
parts
of
your
car
when
installed.

©
NEVER
operate
the
amplifier
without
the
proper
power
and
ground
wire.
(10
gauge
minimum)
©
NEVER
operate
the
amplifier
without
proper
fusing.
Fuse
holder
must
be
located
within
18’
from
the
battery.
This
fuse
is
to
protect
the
car
not
the
electronics.
In
case
of
a
short,
the
fuse
will
blow
instead
of
the
wire
burning
up.
Using
other
than
the
recommended
fuse
ratings
at
the
battery
and
at
the
amplifier
may
cause
damage
to
the
amplifier
and
will
void
your
warranty.
®
Do
not
run
wiring
underneath
or
outside
the
car
since
such
exposure
to
the
elements
may
cause
the
insulation
to
deteriorate
rapidly,
resulting
in
short-
circuits
and/or
intermittent
operation.
All
cables
should
be
run
beneath
carpets
and
inside
trim
pieces.
®
To
help
minimize
interference,
it
is
best
to
run
the
power
cables
along
the
opposite
side
from
the
audio
cables.
©
Wherever
wires
pass
through
metal,
rubber
or
plastic
grommets
must
be
used
to
prevent
the
metal
from
wearing
through
the
insulation
and
causing
a
short.
e@ Whenever possible, use cable ties, mounting clamps
and similar wiring aids (available from an electrical
supply
or
auto
parts
store).
Adding
stress
relief
loops
to the wiring is also advisable to prevent straining or
breakage.
@ It is best to test the system before the amplifier is
mounted and interior of car is reassembled.
e@
If
the
temperature
inside
your
car
reaches
extreme
levels
(such
as
sitting
locked
up
for
several
hours
in
the
hot
sun
or
exposed
to
a
very
cold
winter's
day)
the
‘amplifier
may
go
into
protection
mode
and
shut
off.
Leave
the
unit
off
until
the
ambient
temperature
returns
to
normal.
e@ The XA-5450 operates with any vehicle using a 12-
volt negative ground system. If you are not sure of the
type of electrical system in your vehicle, consult your
authorized Sherwood dealer or qualified mechanic.
e@ NEVER ground the speaker leads and NEVER allow
the
speaker
leads
to
come
in
contact
with
each
other.
Speaker wire should be 18 gauge or larger.
@ Remote turn on wire must be switched by the radio. If
the
radio
does
not
have
a
remote
turn
on
or
antenna
output,
connect
to
wire
that
has
a
positive
12-volts
when
the
key
is
turned
to
the
accessory
position.
If
the
amplifier
does
not
turn
off
the
battery
will
die.
@ Do not listen to high volumes for extended periods of
time or hearing damage may occur.

Installation
MOUNTING:
. After reading precautions decide where you are
going to install the unit. Also, see Fig. 1 and Fig. 2.
. Once the location has been determined, place the
amplifier in position. Using a felt tip pen or pencil mark
the six holes to be drilled for mounting. NEVER use
the amplifier as a template for drilling. It is very easy
to damage the amplifier surface in this manner.
.
Remove
amplifier.
Drill
six
3.6
m.m.(9/64
inch)
Fig.
1
Mounting
Position
diameter
holes
into mounting
surface.
. If possible test the system operation before final
mounting of the amplifier.
. Mount the amplifier using the supplied 6 self threading
screws.
Screw 1WPTC 4x25
Drill
¢
3.6
m.m.
Hole
Fig.
2
On-Chassis
Mounting

Input Connections
This amplifier will accept low level inputs only. Low level
is the same as line level or preamp level. Low level signal
is carried through RCA cables. Be sure that the head unit
is equipped with the Low Level outputs.
1. Low level/line input-Connect RCA cables from head
unit, or other signal processor, to the line level input on
the amplifier. See Fig. 3. Low level input Connections.
If the amplifier is to be used to drive one speaker in the
bridged mode, both inputs must be used.

(1)
SINGLE
AMPLIFIER
CONNECTION
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Low
Level
Input
Connections

Amp used to power
"full
Range"
speakers
or coaxials
Amp used to power
Subwoofers
or coaxials
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Note: Switch Setting on front side
7. HIGH PASS FILTER-“120” or “180”
Right LOW PASS FILTER- “OFF”
Left BASS EQ-“OFF”
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Note: Switch settings on front side
HIGH PASS FILTER-“OFF”:
LOW PASS FILTER-“60” or "120"
BASS EQ-"OFF" or "ON"
Adjust BASS EQ
Level as needed

Speaker Connections
This amplifier can operate in either one, two or three
channel mode. The minimum impedance for two channel
operation is 2 ohms per channel. The minimum
impedance for single channel (bridged/mono) operation
is 4 ohms. Three channel tri-power is referred to stereo
and mono at the same time. Minimum impedances
remain the same for three channel (satellite/subwoofer)
systems as long as proper passive crossovers are used.
Connect right and left speaker wires to corresponding
speaker output terminals of the amplifier. Be sure to have
the positive wire from the speaker to the positive speaker
terminal ‘of the amplifier and the negative wire from the
speaker must connect with the negative speaker terminal
of the amplifier. Reversing any of these connections will
result in the speaker cones moving out of phase which
causes bass cancellation. See Fig. 4. Speaker Output
Connections.
Tri-Power Speaker Connections
With the extreme flexibility of the Sherwood XA-6450, we
highly recommend that you carefully design the entire
system BEFORE its installation. The amplifier's “TRI-
POWER” feature allows the amplifier to power a pair of
satellites or coaxials and add on a single subwoofer. This
means the amplifier is operating in stereo and mono at
the same time. As previously mentioned earlier the
minimum impedance for stereo is 2 ohms per channel
and 4 ohms for mono. For this to all work together,
passive crossovers must be utilized. These crossovers
are a combination of coils and capacitors to creat a high
pass for the mid/tweeter combination and a low pass for
the subwoofer. A high pass crossover eliminates all
frequencies below the crossover frequency (cutting the
bass out of the highs). A low pass crossover eliminates
all frequencies above the crossover frequency (cutting
the highs out of the bass). The following crossover chart
(6 dB per octave) is for your reference. In this application
the low pass and high pass switch on the amplifier must
be in the “OFF” position. The coils and capacitors are
available through most electronic stores and most car
audio dealers. See Fig. 5 for chart and diagram.

Note : For mono mode, connect the positive lead of the speaker to the (MONO+) terminal of the amplifier and the negative lead
to the (MONO-) terminal.
(1)
STEREO
SINGLE
AMPLIFIER
CONNECTION
NOTE: Switch settings on front side
HIGH PASS FILTER -“120, 180 or OFF”
LOW PASS FILTER - “OFF”
BASS EQ - “OFF”
MAIN SPEAKER
(2)
STEREO
AND
MONO
SUBWOOFER
TWO
'AMPLIFIER
CONNECTIONS
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Fig. 4 Speaker Output Connections

Fig .6. Tri-Power Connections
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LOW PASS
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SUBWOOFER
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HIGH PASS
CROSSOVER
(NOT INCLUDED)
MAIN SPEAKERS
SSOVER
(NOT INCLUDED)

Power Connections
It is important to have good quality power and ground
connections. Remember, to complete an electrical circuit,
the ground connection is just as important as the positive
power connection. Before any power connections. are
made, disconnect the ground cable at the battery.
Minimum battery cable size is 10 gauge.
Ground-Connect the proper gauge ground wire to the
amplifier “GND” terminal. Locate the position on the
chassis of the car to which the amplifier is to be
grounded. The surface must be free from any paint or
dirt. This can be accomplished with a small grinding bit or
wire wheel.
NOTE: Do not ground amplifier to the “frame” of the car,
the frame on most cars and trucks is not grounded to the
chassis (body). Solder or crimp ring terminal to ground
wire. Predrill the prepped chassis metal to bolt the
ground ring terminal with nut, bolt and lock washers.
Insulate metal and connector with paint or silicon to
prevent rust and oxidation. Silicon also works great to
prevent nuts and bolts from working loose in a harsh
environment of an automobile. Upon completion of
ground connection, grab wire or connector and confirm
that it is a solid connection. To prevent engine noise, it is
recommended to ground the head unit and other audio
electronics in the same location.
12
Remote Turn-on-Connect smaller light gauge wire to
“REMOTE” terminal of amplifier and to remote/antenna
turn-on output of head unit. If head unit is not equipped
with a remote/antenna output, locate a wire that is
controlled by the accessory position of the key. It is
important to have the amplifier turn off with the radio or
key. If the amplifier remains on, the result will most likely
be a dead battery.
Positive-Connect the proper size wire to the amplifier
“B+” terminal of amplifier. Run wire towards the fuse
holder that is no greater than 18 inches from the battery.
Remember, the fuse is to protect the safety of the car in
the case of a short. Connect fuse holder to battery,
however, do not install fuse at this time.

Adjustments
High pass filter-The "HIGH PASS FILTER" is a three
position switch “180, 120, OFF”. The electronic high
pass filter cuts out the bass from the mids/highs and will
pass all frequencies above 120 or 180 hertz. The final
decision between “120” and “180” will be based on the
final listening of the system and speaker's ability to play
lower frequencies. If the amplifier is to power
subwoopers place the “HIGH PASS FILTER” to the
“OFF” position.
Low pass filter-The “LOW PASS FILTER’ is a three
position switch “120, 60, OFF”. If the channels are only
to be used to power subwoofers, the switch should be at
either at the “60” or the “120” position. This will cut out
all high frequencies above 60 or 120 hertz. The final
decision between "60" and "120" will be based on the
final listening of the system. If the amplifier is to power
full range speakers place the "LOW PASS FILTER" to
the “OFF” position.
After initial adjustments have been made, install fuse
(same rating as that labeled on the amplifier) into the
fuse holder at the battery.
Level adjustments- The sensitivity adjustments is to
allow the amplifier to work with many different brands of
head units. It allows input signal to vary between 250
millivolts to 2 volts from the head unit or other signal
processor.
13
Start by setting the sensitivity adjustments to the
"MIN
“(2
volts).
Using
a
cassette
or
compact
disc
that
you
are
familar
with,
turn
on
head
unit
to
the
3/4
volume
setting.
Slowly
turn
up
sensitivity
adjustment
towards
the
"MAX"(250
milivolts)
using
a
small
flat
head
screw
driver.
Stop
turning
on
the
onset
of
distortion
and
turn
back
just
a
slight.
The
3/4
volume
setting
is
now
the
"maximum"
volume
for the
head
unit.
The goal is to keep the level control to the lowest setting
yet still have enough signal to drive the amplifier. This is
done to prevent over driving the amplifier and to keep
system noise to a minimum. It is important not to over
drive the speakers (at point of distortion) as this will
cause permanent damage to the speakers. Also, if the
amplifier itself is over driven, it could be damaged.
Bass EQ. The "BASS EQ“ feature is the variable boost
from 0 dB to + 6 dB. This may or may not be required for
the system. If the BASS EQ is required switch it to the
"ON" position and carefully adjust the BASS EQ LEVEL.
Remember, a +6dB boost in signal requires the amplifier
to work 10 times harder. Again, do not over drive the
speakers or the amplifier.

Troubleshooting Guide
This
section
provides
you
with
a
catalog
of
amplifier
symptoms
and
their
probable
causes
and
solutions.
Before
you
consult
this
listing,
make
sure
the
vehicle's
electrical
system
is
working
properly
by
verifying
that
other
electical.items(e.g.
headlight,
Windows
etc.) still function correctly.
SYMPTOM
No Sound
Audio cycles
on and off
Distorted Audio
Audio level low
Audio lacks
External fuse
blowing
Whining noise on
audio with engine
running
Ticking noise on audio
with engine running
PROBABLE CAUSE
Low or No Remote
Turn-On connections
Blown Fuse
Power wires not connected
Blown speakers or
not connceted
Thermal Protection Circuits
are properly shutting amplifier
off each time it gets too hot
Input Sensitivity not set properly
or damaged speaker cones
Low turn-on voltage .
Mute circuits is on Head unit
Speaker wired with wrong polarity,
cause cancellation of bass
frequencies
Incorrect wiring or
short circuit
Amplifier is picking
up alternator noise
Amplifier is picking up
radiated spark noise
14
SOLUTION
Check remote turn-on voltage at amp
and head unit
Repalce with new fast-blow fuse
Check butt splices or solder joints
check Ground and Battery connections
Use VOM or DVM to measure speaker coil
impedance; check spaker wiring connections
Check location for adequate ventialtion
check speaker wiring for a short to chassis
Check speaker impedance and refer to speaker conections
See adjustment procedure and check each step;
inspect each speaker for damage and repair or
suspected component
Refer to head unit owner's manual
Check electrical system for low voltage;
check ground connection
Check polarity of wires from amplifiers to each speaker
as defined by the system design; check battery voltage at
amplifier during operation
Refer
to
Electrical
Installtion
and
check
each
installtion
step
Install
an
in-line
noise
filter
on
the
head
unit's
power
wire;
check
alternator
routing
diodes
or
voltage
regulator
for
proper
operation.
Check
all
grounds,
check
battery
voltage
Check RCA audio cables routes; Install an in-line
noise
filter
on
the
head
unit's
power
wire.
Check
spark
plug
wires

SPECIFICATIONS
m Amplifier Sections
m MAX POWER (EIA)
450Wx1
— QO5Wx2
eo Mono Mode
e@ Stereo Mode
fe Signal to Noise Ratio
le Channel Separation
@ Operating
@ Speaker Impedance (Minimum)
@ Dimensions( Inches
RMS Power(4 Ohms)
Le Mono Mode
e Stereo Mode
220Wx1
20Hz - 20KHz
5 Hz - 80KHz
102dB
@ Power Bandwidth
e@ Frequency Response
e Signal to Noise Ratio
@ Damping Factor
@ Channel Separation >» 65dB
Note
:
Specifications
&
design
subject
to
change
without
notice
for
improvement.
15