Kenwood KM-991 User manual

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STEREO POWER AMPLIFIER
KM-991
INSTRUCTION
MANUAL
KENWOOD CORPORATION
338-00 GD ( _Y)[GA]

Introduction
PT
Your
choice
of
this
product
indicates
that
you
are
a
devotee
to
excellence
in
sound
reproduction.
We
appreciate
your
patronage
and
take
pride
in
the
long
tra-
dition
of
quality
components
that
our
company
represents.
So
that
you
can
get
the
most
out
of
your
unit,
we
suggest
that
you
take
the
time
to
read
through
this
manual
before
you
hook
up
and
operate
your
system.
This
will
acquaint
you
with
operating
features
and
system-connection
consid-
erations
so
that
your
listening
pleasure
will
be
enhanced
right
from
the
start.
You
will
notice
that
in
ail
aspects
of
planning,
engineering,
styling,
operating
convenience
and
adaptability
we
have
sought
to
anticipate
your
needs
and
desires. Accessory
Keep this manual handy for future reference.
AC plug adaptor
For your records (except for some areas)
Record the serial number, found on the back of the unit, in For the unit with a European AC
the
spaces
designated
on
the
warranty
card,
and
in
the
plug
in
areas
other
than
Europe.
space
provided
below.
Refer
to
the
model
and
serial
num-
bers
whenever
you
call
upon
your
dealer
for
information
or
service
on
this
product.
Model__________—___ Serial Number
Unpacking
Unpack the unit carefully and make sure that all accessories
are put aside so they will not be lost.
Examine the unit for any possibility of shipping damage. If
your
unit
is
damaged
or
fails
to
operate,
notify
your
dealer
immediately. If your unit was shipped to you directly, notify
the shipping company without delay. Only the consignee
(the person or company receiving the unit) can file a claim
against the carrier for shipping damage.
We recommend that you retain the original carton and pack-
ing materials for use should you transport or ship the unit in
the future.
Conte
nts
Caution:
Read
the
pages
marked
A
carefully
©
ensure
safe
operation.
Introduction Controls and indicators
A.
Before
applying
power
Operating
instructions
A Safety precautions Listening to the program source
A IMPORTANT SAFEGUARDS Listening through headphones
System connections POWER LEVEL METER
To AC outlets In case of difficulty
Connection of speakers AY Specifications
Setting the SPEAKER IMPEDANCE SELECTOR
2 = KM-991 (En)

A\
Caution:
Read
this
page
carefully
to
ensure
safe
operation.
Before applying power
Seen
eee
eee
ee
nace
cece
For the U.S.A. and Canada
Important!
Units shipped to the U.S.A. and Canada are designed for opera-
tion on 120 volts AC only.
CAUTION:
To
PREVENT
ELECTRIC
SHOCK
DO
NOT
USE
THE
AC
PLUG
WITH
AN
EXTENSION
CORD,
RECEPTACLE
OR
OTHER
OUTLET
UNLESS
THE
BLADES
CAN
BE
FULLY
IN-
SERTED
TO
PREVENT
BLADE
EXPOSURE.
For the United Kingdom
Important!
Units
shipped
to
the
U.K.
are
designed
for
operation
on
240 volts AC only.
The
mains
plug
must
be
removed
from
the
wall
socket
prior
to
any
internal
examination.
The
wires
in
this
mains
lead
are
coloured
in
accordance
with
the
following
code:
;
Neutral
The
wires
in
this
mains
lead
must
be
connected
to
the
termi-
nals
in
the
plug
as
follows:
Wire
colour
Piug
terminal
marking
N or Black
Brown to
Live
Blue to
Neutral * )
Plug
Notes:
1. If a 13-amp plug is used, this must be fitted with a 5-amp
fuse.
2.
If
a
3-pin
plug
with
earthing
contact
is
used,
no
wire
must
be
connected
to
the
E terminal.
Safety precautions
For Australia and Europe
Important!
Units
shipped
to
Australia
are
designed
for
operation
on
240
V
AC only.
Units
shipped
to
Europe
are
designed
for
operation
on
230
V
AC
only.
For other countries
Important!
Units
shipped
to
countries
other
than
the
above
countries
are
equipped
with
an
AC
voltage
selector
switch
on
the
rear
panel.
Refer
to
the
following
paragraph
for
the
proper
setting
of
this
switch.
AC voltage selection
This
unit
operates
on
110-120
or
220-240
volts
AC.
The
AC
voltage
selector
switch
Type
A
or
Type
B
on
the
rear
panel
is
set
to
the
voltage
that
prevails
in
the
area
to
which
the
unit
is
shipped.
Before
connecting
the
power
cord
to
your
AC
out-
let,
make
sure
that
the
setting
position
of
this
switch
matches.
your
line
voltage.
If
not,
it
must
be
set
to
your
voltage
in
ac-
cordance
with
the
following
direction.
Note:
———__—$__$$
Our
warranty
does
not
cover
damage
caused
by
excessive
line
voltage
due
to
improper
setting
of
the
AC
voltage
selector
switch.
AC voltage selector switch
—- <—
AC110-
120V ~ AC220V~ AC240V~
_
mall
AC110V- <<» AC220V-
120V~ 240V ~
Move switch lever to match your line voltage with
a small screwdriver or other pointed tool.
WARNING:
TO
PREVENT
FIRE
OR
ELECTRIC
SHOCK,
DO
NOT
EXPOSE
THIS
APPLIANCE
TO RAIN OR MOISTURE.
CAUTION
Wo SAGER
CAUTION:
TO
REDUCE
THE
RISK
OF
ELECTRIC
SHOCK,
DO
NOT
REMOVE
COVER
(OR
BACK).
NO
USER-SERVICEABLE
PARTS
INSIDE,
REFER
SER-
1 OVEN VICING TO QUALIFIED SERVICE PERSONNEL.
THE
LIGHTNING
FLASH
WITH
ARROWHEAD
SYMBOL,
WITHIN
AN
EQUILATERAL
TRIANG
LE,
IS
INTENDED
TO
ALERT
THE
USER
TO
THE
PRESENCE
OF
UNINSULATED
‘‘DANGEROUS
VOL-
TAGE”
WITHIN
THE
PRODUCT'S
ENCLOSURE
THAT
MAY
BE
OF
SUFFICIENT
MAGNITU
DE
TO
CONSTITUTE
A
RISK
OF
ELECTRIC
SHOCK
TO
PERSONS.
THE
EXCLAMATION
POINT
WITHIN
AN
EQUILATERAL
TRIANGLE
IS
INTENDED
TO
ALERT
THE
USER
TO
THE
PRESENCE
OF
IMPORTANT
OPERATING
AND
MAINTENANCE
(SERVICING)
IN-
STRUCTIONS
IN
THE
LITERATURE
ACCOMPANYING
THE
APPLIANCE.
KM-991 (En)
3

IMPORTANT
SAFEGUARDS
Please
read
ail
of
the
safety
and
operating
instructions
before
operating
this
unit.
For
best
results,
follow
all
warnings
placed
on
the
unit
and
adhere
to
the
operat-
ing
and
use
instructions.
These
safety
and
operating
in-
structions
should
be
retained
for
future
reference.
1.
Power
sources
—
The
unit
should
be
connected
to
a
power
supply
only
of
the
type
described
in
the
operating
instructions
or
as
marked
on
the
appliance.
2.
Power-cord
protection
—
Power-supply
cords
should
be
routed
so
that
they
are
not
likely
to
be
walked
on
or
pinched
by
items
placed
upon
or
against
them,
pay
particular
attention
to
cords
at
plugs,
convenience
receptacles,
and
the
point
where
they
exit
from
the
unit.
Never pull or stretch
the cord.
3.
Grounding
or
polarization
—
The
precautions
should
be
taken
so
that
the
grounding
or
polariza-
tion
means
of
this
unit
is
not
defeated.
4.
Ventilation
—
The
unit
should
be
situated
so
that
its
location
or
position
does
not
interfere
with
its
proper
ventilation.
To
maintain
good
ventilation,
do
not
put
records
or
a
table-cloth
on
the
unit.
Place
the
unit
at
least
10
cm
away
from
the
walls.
Do
not
use
the
unit
on
a
bed,
sofa,
rug
or
similar
surface
that
may
block
the
ventilation
openings.
5.
Water
and
moisture
—
The
unit
should
not
be’
used
near
water
—
for
example,
near
a
bathtub,
washbowl,
kitchen
sink,
laundry
tub,
in
a
wet
base-
ment,
or
near
a
swimming
pool,
etc.
6.
Temperature
—
The
unit
may
not
function
pro-
perly
if
used
at
extremely
low,
or
freezing
tempera-
tures. The ideal ambient temperature is above +5°C
(47°F).
4 kM-991 (En)
A\
Caution
:
Read
this
page
carefully
to
ensure
safe operation.
7.Heat
—
The
unit
should
be
situated
away
from
heat
sources
such
as
radiators,
heat
registers,
stoves,
or
other
units
(including
amplifiers)
that
produce
heat.
.
Electric
shock
—
Care
should
be
taken
so
that
ob-
jects
do
not
fall
and
liquid
is
not
spilled
into
the
en-
closure
through
openings.
If
a
metal
object,
such
as
a
hair
pin
or
a
needle,
comes
into
contact
with
the
inside
of
this
unit,
a
dangerous
electric
shock
may
result.
For
families
with
children,
never
permit
chil-
dren
to
put
anything,
especially
metal,
inside
this
unit.
9.Enclosure
removal
—
Never
remove
the
en-
closure.
If
the
internal
parts
are
touched
accidentally,
a
serious
electric
shock
might
occur.
10.
Magnetic
fields
—
Keep
the
unit
away
from
sources
of
magnetic
fields
such
as
TV
sets,
speaker
systems,
radios,
motorized
toys
or
magnetized
objects.
11.
Cleaning
—
Do
not
use
volatile
solvents
such
as
alcohol,
paint
thinner,
gasoline,
or
benzine,
etc.
to
clean
the
cabinet.
Use
a
clean
dry
cloth.

12. Carts and stands — An appliance and cart com-
13.
14.
15.
16
17
bination should be moved with care. Quick stops,
excessive
force,
and
uneven
surfaces
may
cause
the
appliance and cart combination to overturn.
LA
——
Nonuse
periods
—
The
power
cord
of
the
unit
should
be
unplugged
from
the
outlet
when
left
un-
used
for
a
long
period
of
time.
Abnormal
smell
—
|f
an
abnormal
smell
or
smoke
is
detected,
immediately
turn
the
power
OFF
and
pull
out
the
power
cord.
Contact
your
dealer
or
nearest
service
center.
POWER
OFF!
Damage
requiring
service
—
The
unit
should
be
serviced
by
qualified
service
personnel
when:
A.
The
power-supply
cord
or
the
plug
has
been
damaged;
or
B.
Objects
have
fallen,
or
liquid
has
been
spilled
into
the
unit;
or
C. The unit has been exposed to rain; or
D.
The
unit
does
not
appear
to
operate
normally
or
exhibits
a
marked
change
in
performance;
or
E.
The
unit
has
been
dropped,
or
the
enclosure
damaged.
Servicing
—
The
user
should
not
attempt
to
ser-
vice
the
unit
beyond
that
described
in
the
operating
instructions.
All
other
servicing
should
be
referred
to
qualified
service
personnel.
Outdoor
antenna
grounding
—
If
an
outside
an-
tenna
is
connected
to
the
receiver,
be
sure
the
an-
tenna
system
is
grounded
so
as
to
provide
some
protection
against
voltage
surges
and
built
up
static
charges.
Section
810
of
the
National
Electrical
Code,
ANSI/
NFPA
No.
70—1984,
provides
information
with
respect
to
proper
grounding
of
the
mast
and
supporting
structure,
grounding
of
the
lead-in
wire
to
an
antenna
discharge
unit,
size
of
grounding
con-
A
Caution
:
Read
this
page
carefully
to
ensure
safe operation.
ductors,
location
of
antenna-discharge
unit,
connec-
tion
to
grounding
electrodes,
and
requirements
for
the
grounding
electrode.
See
Figure.
EXAMPLE OF ANTENNA GROUNDING AS PER
NATIONAL ELECTRICAL CODE
ANTENNA
GROUND
ANTENNA
DISCHARGE UNIT
(NEC SECTION 810-20)
ELECTRIC
RVICE
(NEC SECTION 810-21)
GROUND CLAMPS
POWER SERVICE GROUNDING
ELECTRODE SYSTEM
NEC — NATIONAL ELECTRICAL CODE (NEC ART 250, PART H)
18.
Power
lines
—
An
outdoor
antenna
should
be
lo-
cated away from power lines.
19.
AC
outlets
—
Do
not
connect
other
audio
equip-
ment
with
a
power
consumption
larger
than
that
specified
to
the
AC
outlet
on
the
rear
panel.
Never
connect
other
electrical
units,
such
as
an
iron
or
toaster,
to
it
to
prevent
fire
or
electric
shock.
Notes:
a
1,
Item 3 is not required except for grounded or polarized equipment.
2.
Item
17
and
18
are
not
required
except
for
units
provided
with
antenna
terminals.
3. ftem 17 complies with UL in the U.S.A.
KM-99°8 (En)
5

System connections
Make
connection
as
shown
below.
When
connecting
the
related
system
components,
refer
also
to
the
instruction
manuals of the related components.
Do
not
plug
in
the
power
lead
until
all
connections
are
completed.
Control amplifier KC-991
ALD110-120V /AC220-240V~
50/60rz
‘SWITCHED:
‘TOTAL SBOW MAX.
O |
% eenren | Rear ieg
SPEAKER IMPEDANCE SELECTOR
(Except for some areas.)
To AC
outlet
Power amplifier KM-991
AC 410V- are= AC 220V-
421 240v~
AC voltage selector switch Unswitched AC outlets
(Except for some areas.)
To AC outlet
i
inati
UNSWITCHED
AC
outlet
ence
Shape
of
the
AC
outlet
The
power
of
the
component
connected
to
this
For
U.S.A.,
Canada
ini
=
AC
aye
=
be
switched
ON/OFF
reg
ard-
and
U.S.
Military
ess
of
the
ER
key
on
the
main
unit.
For other countries
Notes:
1.
Connect
all
cords
firmly.
if
connections
are
loose
there
could
be
loss
of
sound
or
noise
produced.
2.
When
plugging
and
unplugging
connection
cords,
be
sure
to
first
remove
the
power
cord
from
the
AC
outlet.
Plugging/unplugging
corsnec-
tion
Cords
without
removal
of
the
power
cord
can
cause
malfunctions
or
damage
to
the
unit.
3. Do not connect up a power source which is larger than that indicated on the socket at the rear of the unit.
6 kM991 (En)

Connection of speakers
@® Push the lever up.
Speaker
system A
® Insert the cord.
@ Lock the lever.
Never short-circuit the + and - speaker cords.
If
the
left
and
right
speakers
are
connected
inversely
or
if
the
speaker
cords
are
connected
with
reversed
polarity,
the
sound
becomes
unnatural
with
ambiguous
acoustic
image
posi-
tioning.
Be
sure
to
connect
the
speakers
and
Speaker
speaker
cords
correctly.
system
B
™@
Setting
the
SPEAKER
IMPEDANCE
SELECTOR
(Except
for
some
areas)
According
to
the
impedance
of
the
speakers
used,
set
_
the
SPEAKER
IMPEDANCE
SELECTOR
on
the
rear
panel
as
shown
in
the
table.
Speaker Impedance Selector position
"LESS THAN 8.2"
82,
162
“8
Q
OR
MORE"
@
During
speaker
system
connection
and
operation
of
the
SPEAK-
ER
IMPEDANCE
SELECTOR,
set
the
POWER
key
to
OFF.
@
When
only
one
set
of
speakers
is
used,
use
tne
SPEAKER
A
terminals.
CC®
@
Even
when
only
one
of
speaker
systems
A
and
B
uses
4Q.
or
eS
Finnie.
cle
6Q
speakers,
be
sure
to
set
the
SPEAKER
IMPEDANCE
a
on
Mone
SELECTOR
to
“LESS
THAN
8
Q”.
Speaker
protection
circuit
;
if
the
POWER
switch
of
this
unit
is
turned
on
with
the
speaker
cord
short-circuited,
the
speaker
protection
circuit
will
be
activated
automatically
and no sound will be output.
In
this
case,
remove
the
short
circuit
of
the
speaker
cord
and
then
turn
the
POWER
switch
on
again
to
restore
normal
operation.
kmog1 4en) 7

Controls and indicators
POWER SPEAKERS A/B POWER LEVEL
switch switches METER
Headphones jack POWER INDICATOR METER RANGE
(PHONES) , knob
SPEAKERS A and B switches
A,B OFF — This position silences all speakers to permit private use * SPEAKERS 5
of headphones. :
AON — Activates speakers connected to the SPEAKERS A ter- (C—F ic
minals on the rear panel.
BON — Activates the speakers connected to the SPEAKERS B
terminals on the rear panel.
A,BON — Activates the speakers connected to the SPEAKERS A
and B terminals simultaneously.
@ When speakers are connected only to the SPEAKERS A termi-
nals, the sound will not be heard if both the SPEAKERS A and B
switches are depressed to the ON position.
8 ki-9¢1 (En)

Operating instructions
Mi Listening to a program source
1 Switch the power on.
Select an input source on the control
amplifier.
@ The audio signal of that source will be input from the con-
trol amplifier connected to this unit.
Adjust the volume on the control amplifier.
@ The output level is displayed on the POWER LEVEL
METER.
Adjust the tone on the control amplifier.
POWER LEVEL METER
Listening through headphones
Insert the headphone plug into the
headphones jack.
PHONES:
©
@
Set
the
SPEAKERS
switch
so
that
both
speaker
systems
A
and
B
are
OFF.
2
Adjust
the
volume
on
the
control
amplifier.
@
Be
sure
to
minimize
the
volume
before
unplugging
the
headphone
plug.
The
POWER
LEVEL
METER
can
display
the
output
power
level
up
to
200
watts.
However,
it
is
rather
rare
that
you
play
music
at
such
nigh
lev-
els
as
50
or
200
watts
at
your
home.
In
usual
cases,
the
meter
sensitivity
can
be
boosed
by
ten
times
to
display
the
level
more
finely.
Set the METER RANGE knob to the x0.1 position.
METER RANGE
x09
x4
Levels from 0.01 watt to 200 watts can be displayed.
To
return
to
the
normal
sensitivity,
set
the
switch
to
the
x1
posi-
tion.
The POWER LEVEL METER displays the levels from 0.4 to 200
watts
assuming
that
the
speaker
impedance
is
8
ohms.
If
the
impedance of your speakers is other than 8 ohms, the POWER
LEVEL METER may not display correct values.
KM-991 (En) 9

In case of difficulty
What appears to be a malfunction may not always be serious. If your unit should not perform as expected, consult the
table
below
to
see
if
the
problem
can
be
corrected
before
seeking
help
from
your
dealer
or
service
representative.
Sympiom Ceuse
Power is on but no sound. @ Poor connection at wall outlet. Power outlet
(Indicator is off.) inactive.
® Check outlet using a lamp or other appli-
ance (outlet may be controlled by a wall
switch).
@ Turn the POWER switch OFF, identify
and remove the cause, and turn the
POWER switch ON again.
@ Protection circuitry operating.
Sound is not output.
(Indicator lights.)
@ The speaker cords are disconnected. @ Connect them properly referring to
“System connections”.
@ Adjust the control amplifier's volume to a
proper level.
@ Check speaker switch.
@ Turn the power off, eliminate the short
circuiting, then turn on the power again.
@ The VOLUME is set to the minimum position.
@ Speaker switched off.
@ Speaker cords are short-circuited.
@ Audio cords are short-circuited.
Sound is not output from one of the
speakers.
@ The speaker cord is disconnected. @ Connect it properly referring to “System
connections”.
@ Adjust the Left/Right balance.
@ The BALANCE control is set to an extreme
position.
Note:
Do not use contact cleaners because it could cause a malfunction. Be specially careful against contact cleaners containing oil, for they may
deform the plastic components.
10 kN4-991 fn}

S
p
ec
ifi
cati
0
ns
Ay
Caution:
Read
this
page
carefully
to
ensure
safe
operation.
For U.S.A. and Canada
Rated Power Output
150
watts
per
channel
minimum
RMS,
both
channels
driven,
at
8
Q
from
20
Hz
to
20,000
Hz
with
no
more
than
0.03%
total
harmonic
distortion.
(FTC)
Total Harmonic Distortion
20
Hz
to
20,000
HZ.......ccssceccesccssceesessceesersseeenese
0.015%
at
1/2
rated
power
into
8Q
VV
Z
oo.
cicascved
cxcssuscdesascacssovceiasds
covsccesessaevaieessiesessas
0.002%
at
1/2
rated
power
into
8Q
Inter Modulation Distortion
(60 Hz:7 kHz = 4:1)
0.002% at rated power into 8Q
5 Hz to 200 kHz, +0 dB, -3 dB
Frequency Response
Signal-to-Noise
Ratio
(IHF-A)..........---ssssesssssessees
120
dB
(MAIN
IN)
Damping
Factol...........ccessserssscesseeecerenensesseneeenens
More
than
35
at
50
Hz
into
8Q
General
Power
Consumption
...........scccecccessseenrreeeserenseenenenee
5A
AC
outlets
UNSWITCHED
...........:sscsccscsssssscresnrensaneresnssensnee
2;
(Total
100
W,
0.8
A
max.)
DIMEMNSIONS..........00..-ccccccscsneeneseevsnssceecsnsnacenesrersanense
W:
440
mm
(17-5/6")
H: 133 mm (5-1/4")
D: 276 mm (10-7/8")
Weight
(net).........ssscccesscesssseseeesesenesseneeesesensnseenes
8.6
kg
(19.0
Ib)
For Other Countries
Rated Power Output
(IHF
"66)
from
20
Hz
to
20,000
Hz
0.03%
T.H.D.
at
80........ccccccescoseesseeessnsesensereeseees
150
W
+
150
W
Music
Power
(8
Q).........:-scsssssscsersreenseenerssssseeseenees
310
W
+310
W
Total
Harmonic
Distortion
.
20
Hz
to
20,000
HZ..........scssesssssseeresssseressescereene
0.015%
at
1/2
rated
power
into
8Q
VKH
Z
..cceccccsccssovceccsverssnrerssnrsnnccsccccarscnnencssessoseaaes
0.002%
at
1/2
rated
power
into
8Q
Inter
Modulation
Distortion
(GO
Hz:7
KHZ
=
4:1)
....ccscsescecsesesscecseeverenesnersssenens
0.002%
at
rated
power
into
8Q
Frequency
ReSponse............cssessceseeeseees
...
5
Hz
to
200
kHz,
+0
dB,
-3
dB
Signal-to-Noise
Ratio
(IHF-A)
“3
120
dB
(MAIN
IN)
Damping
Factol..........scccssescsensseeessresneseersesssseaeseens
More
than
35
at
50
Hz
into
8Q
General
Power
Consumption.
...........ssereccesersesseeneensseneens
350
W
(IEC)
AC
outlets
UNSWITCHED...........:ccescesssccsesceesssereeeneesroetsees
2;
(Total
200
W
max.)
DIMENSIONS...........::cscresesceeeseesereeerestseesesnerescerseeteaes
W:
.440
mm
H: 133 mm
D: 276mm
Weight
(Net)
..........-cscssesssserensserensesessessessnesseases
8.6
kg
(19.0
Ib)
Note:
KENWOOD
follows
a
policy
of
continuous
advancements
in
development.
For
this
reason
specifications
may
be
changed
without
notic
&.
KM-991 (EP) 11

KENWOOD