Kenwood L-A1 User manual

KE NWO OC D Ze \e A l Instruction Manual
= INTEGRATED AMPLIFIER

Introduction
Thank you for buying the Kenwood L-A1 integrated amplifier.
Please read this manual carefully to ensure that you get the greatest possible use and satisfaction from your amplifier.
Keep this manual in a safe place for future reference.
Contents Caution: Read the pages marked A\ carefully to ensure safe operation. ‘
es m R Accessories
A
Before
applying
power
3
How
to
use
the
amplifier
12
Make
sure
that
all
accessories
are
put
aside
Listening
through
the
main
source
so
they
will
not
be
lost.
Playing
records
A
Safety
precautions
3
Listening
through
headphones
Muting
the
sound
Remote
control
(1)
A\
Important
safeguards
4
S
P
Z
How
to
record
music
14
Selecting
a
music
source
for
recording
:
og
Listening
to
a
second
music
source
while
recording
About
your
new
Kenwood
L-A1
amplifier
6
ion totind
Recoring
Dubbing
music
fk
;
Listening
to
a
second
music
source
while
dubbing
.
dry
ee
(R6/SUM-3)
12
How
to
set
up
your
new
amplifier
8
Hee
Mn
Me
Temata
Contant)
Troubleshooting
18
Names
of
parts
10
Stand
by mode
of
POWER
switch
Block
diagram
19
Shorting pins (2)
How
to
use
the
remote
control
1
Ass
<A
Inserting
the
batteries
Characteristics
charts
20
Operating the remote control AC plug adaptor (1)
on : {Except for some areas)
Specifications 2) For the unit with a European
a a a AC plug in areas other than
Europe.
N

Before applying power
For Europe
A\ Caution: Read this page carefully to ensure safe operation.
For other countries
important!
Units shipped to Europe are designed for operation on
230 V AC only.
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:
BlUGsxcesecre etn ated ee Neutral
BLOWN): csccsssevabseceiereevednensipencdieths Live
The wires in this mains lead must be connected to the
terminals in the plug as follows:
Wire colour Plug terminal marking
» (BIUO. ss aishditieeenda nies N or Black
BrOWNinn ccs iestasees tevaasiesdosseaeauatys L or Red
| Brown to
Live
Blue to € )
Neutral
N
Plug -—
Notes:
1.
Ifa
13-amp
plug
is
used,
this
must
be
fitted
with
a
13-amp
fuse.
2.
Ifa
3-pin
plug
with
earthing
contact
is
used,
no
wire
must
be
connected
to
the
E
terminal.
Important!
Units shipped to countries not specified on the left-hand side
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 outlet,
make sure that the setting position of this switch matches your
line voltage. If not, it must be set to your voltage in accordance
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.
Safety precautions
AC voltage selector switch
Type A =
AC 110- AC 220-
120V~ 240v~
Type B
AC 110- | AC 22e0V~ AC 230-
OvV~ 240V~
Move switch Jever 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 MOISTU
As
CAUTION CAUTION: TO REDUCE THE RISK OF ELECTRIC SHOCK, DO NOT REMOVE
MISK'OF ECEGTRIS SHOCK COVER (OR BACK). NO USER-SERVICEABLE PARTS INSIDE, REFER
DO NOT OPEN SERVICING TO
QUALIFIED SERVICE PERSONNEL.
THE LIGHTNING FLASH WITH ARROWHEAD SYMBOL, WITHIN AN EQUILATERAL TRIANGLE,
IS INTENDED TO ALERT THE USER T
TO THE PRESENCE OF UNINSULATED “DANGEROUS VOL-
TAGE” WITHIN THE PRODUCT'S ENCLOSURE THAT MAY BE OF SUFFICIENT MAGNITUDE
TO CONSTITUTE A RISK OF ELECTRIC SHOCK TO PERSONS.
THE EXCLAMATION POINT WITH!
THE USER TO THE PRESENCE
N AN EQUILATERAL TRIANGLE IS INTENDED TO ALERT
OF IMPORTANT OPERATING AND MAINTENANCE
(SERVICING) INSTRUCTIONS IN THE LITERATURE ACCOMPANYING THE APPLIANCE.

Important safeguards
A
Caution:
Read
this
page
carefully
to
ensure
safe
operation.
Please read all of the safety and operating instructions before operating
For best results, follow all warnings placed on the unit and adhere
to the operating and use instructions. These safety and operating instruc-
tions should be retained for future reference.
this unit.
Note:
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.
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.
Grounding or polarization — The precautions
should be taken so that the grounding or
polarization means of this unit is not defeated.
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.
Water and moisture — The unit should not be
used near water - for example, near a bathtub,
washbowl, kitchen sink, laundry tub, in a
wet basement, or near a swimming pool, etc.
Temperature — The unit may not function
properly if used at extremely low, or freezing
temperatures. The ideal ambient temperature
is above +5°C (41°F).
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
objects do not fall and liquid is not spilled into
the enclosure 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.
Item 3 is not required except for grounded or polarized equipment.
10.
11,
12.
Enclosure removal — Never remove the en-
closure. If the internal parts are touched
accidentally, a serious electric shock might
occur.
Magnetic fields - Keep the unit away from
sources of magnetic fields such as TV sets,
speaker systems, radios, motorized toys or
magnetized objects.
Cleaning — Do not use volatile solvents such
as alcohol, paint thinner, gasoline, or benzine,
etc. to clean the cabinet. Use a clean dry
cloth.
Carts and stands —- An appliance and cart
combination should be moved with care. Quick
stops, excessive force, and uneven surfaces
may cause the appliance and cart combina-
tion to overturn.

13.
14.
15.
16.
17.
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 — If 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.
Damage requiring service — The unit should be
serviced by qualified service personne! 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
. The unit has been dropped, or the enclo-
sure damaged.
m
Servicing - The user should not attempt to
service the unit beyond that described in the
operating instructions. All other servicing
should be referred to qualified service
personnel.
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.
A\ Caution : Read this page carefully to ensure safe operation.
Stro6mbrytarens POWER beredskapslage
Indikatorn STAND BY tands efter natkabelns anslutning till
ett vagguttag, oavsett str6mbrytarens POWER ttill/
franslag. Detta anger att en liten mangd strém leds till
komponenten som stéd fér minnesinnehallet.
Detta lage kallas fér beredskapslaget. Str6mbrytaren pa
fjarrkontrollen kan anvandas for att sla pa och av str6mmen sa
lange indikatorn STAND BY lyser.
Virtanappaimen (POWER) valmiustila (STAND BY)
Kun laitteen verkkojohto on liitetty pistorasiaan, valmiustilan
merkkivalo syttyy riippumatta virtanappaimen (POWER) asennosta
(ON/OFF). Merkkivalo osoittaa, etta laitteessa on hieman virtaa
muistin sisaltdjen yllapitoa varten, Tata tilaa kutsutaan
valmiustilaksi. Kun valmiustilan merkkivalo (STAND BY) palaa,
laitteen virta voidaan kytkea ja katkaista kaukosaatimella.
Afbrydertastens (POWER) STAND BY funktion
Nar apparatets stremledning er tilsluttet en stikkontakt, lyser
STAND BY indikatoren, uanset om der er taendt ved afbryderen
pa apparatet eller ej. Det angiver, at apparatet bliver forsynet med
enganske lille mzengde stram til opret-holdelse af hukommelsens
indhold.
Denne funktion kaldes STAND BY. Nar STAND BY indikatoren er
teendt, kan stremmen til apparetet slas til og fra med fjernsty-
ringsenheden.
PA/AV-knappens Stand-by funksjon
Nar stromledningen til dette anlegget er satt i en
vekselstramskontakt, vil STAND-BY indikatorlampen lyse enten
PA/AV-knappen er pa-eller avsiatt. Dette betyr at en viss mengde
strom tilfgres anlegget slik at innholdet i minnet ikke gar tapt.
Denne funksjonen kalles Stand-by. Nar indikatorlampen for STAND-
BY er tent, kan strammen slas PA/AV fra fjernkontrollen.

About your new Kenwood L-A1 amplifier
Tan) e)cenacxe me hvaal-lanlrom-}(erar-]mcomare)(si-m ec] ale)
All the power you need and more
® Super C!
All amplifier circuits in the Kenwood L-A1 amplifier
use our newly developed Super C‘ circuits (Super
Constant Current Cascade Circuit). While most
amplifiers use differential amplifier circuits, in
designing the Super C4 we focused on a new way
of reducing the in-phase noise normally suppressed
by using the common-mode rejection ratio (CMRR)
inherent to differential amplifiers. The result was a
dramatic reduction in the noise generated in the
first stages of the amplifier circuits.
+VCC
Ordinary design
OUT
OUT 2
N41
IN2 0
— ts VES
L-A1
4VCC
CC
e Revolving resistor volume
The master volume of the L-Al amplifier uses a
newly developed large-scale (type 32) revolving
resistor volume. While ordinary volumes have a
slider that moves over the resistor, the slider in the
L-A1 is fixed over the volume while the resistor is
rotated. This design eliminates the connection
formerly created by crimping between the printed
circuit board and the resistor and allows the
amplifier to deliver better sound. This revolving
resistor design also makes it possible to realize
special variant control characteristics which in turn
made it possible for us to use a master volume with
the unbelievably low impedance of 1k Q. This gives
you the low impedance you need in actual use, and
reduces the noise generated from the volume and
main amplifier to the barest minimum.
® Multiple-driver system
The power amplification system uses four parallel push-pull circuits with large-scale transistors (Pc=120W),
which make it possible for the L-A1 to produce strong output even when the impedance of speaker systems
has fallen low at some frequencies. In ordinary parallel push-pull circuits, only the power transistors in the
final stage are connected in parallel, while all other driver transistors in the previous stage are usedin common. .
The multi-driver system used in the L-A1, however, includes a group of driver transistors for each group of
power transistors in a design that connects four groups of Darlington circuits in true parallel. This circuit
structure reduces the load on individual transistors, making it possible to gain a stable circuit operation with
sufficient current and less heat.
Ordinary design L-A1
IN t+-———o OUT iNO———~+ —O OUT

e VIG circuits
The power amplification system also uses voltage
interface gate (VIG) circuits which ensure a clean
source of power for your L-A1 free of impurities
such as ripples, load fluctuation, or other inter-
modulation distortion. From the point of view of
the power amplification system, this results in the
same benefits as would be gained from a far more
powerful power system.
e A heatsink design that separates the
final and driver transistors
The large-scale heatsink with a 7 mm thick base is
used in the power amplifier was designed, and
makes it possible to stand up to even loads of 2 Q.
By laying out the final and driver transistors
separately on both sides of the heatsink, it doubles
as a shield to prevent interference between the
large and low current systems.
e A high-capacity toroidal transformer
The Kenwood L-A1 uses a toroidal transformer that
gives off very little magnetic leakage and responds
well to load fluctuation. Combined with aluminum
electrolytic capacitors and with a capacity of as
much as 450VA per transformer, these transformers
give you all the power you need—and more.
rei cele hem ace ice mere]eliatsime(-1-s1e] a
© Separated blocks for a sturdy, rigid
design
The cabinet of the Kenwood L-A1 uses a
frame design composed of 2 mm thick steel plates
held together with 4 mm screws for the kind of
rigidness you don’t often find. By making the
cabinet tough, we’ve created a sturdy, solid
foundation that assures you of a deep, rich sound.
By adopting a frame design where individual parts
are assembled together into a single cabinet, we
have been able to separate blocks such as the
main and subsidiary power units, the input unit,
and the power supply in order to prevent
interference between individua! components.
e A glass epoxy circuit board
In keeping with our aim of making the cabinet sturdy
and rigid, we have also used a glass epoxy circuit
board for the printed board of the Kenwood L-A1
amplifier. Glass epoxy offers excellent characteristics
and lasts for years. And as a material, glass offers
better rigidity than the phenol resins normally used
in audio equipment.
As a final touch, the board has been firmly fixed into
the frame with solid steel studs.
Other features
@ MC/MM dual-head equalizer
Phono cartridges come in either MM or MC types.
To make the best of both, the Kenwood L-A1 uses
a dual-head equalizer. Although dual head equaliz-
ers are gain-switching equalizer amplifiers, by of-
fering a dedicated first-stage for MM and MC
circuits, they give you all the benefits of a dedi-
cated equalizer amplifier.
® Quality machined and extruded parts
All parts, such as panels, knobs and jacks, etc. have
been either precision-machined or extruded to give
you sure contro! and the high degree of reliability
you need.

How to set up your new amplifier
Connect your equipment to the amplifier as shown in the diagram below.
Please read the individual instruction manuals for all equipment being
connected to the amplifier.
Do not plug in the power until after all connections have been completed.
The diagram shows an example of how to connect components to lines 1-3.
Use this as an example of how to properly connect your own equipment.
Digital audio tape (DAT) 1 or Digital audio tape (DAT) 2 or
cassette tape deck 1 cassette tape deck 2
Tuner
(>
—_leZ)
Record player
GND (ground) terminal
Balance input terminals ?
For connection to
wall socket
CD player
@ PHONO terminal shorting pins
When the PHONO terminal is not used, connect the
attached shorting pins to the PHONO terminal. Do not For BS terminals or other devices
connect the pins to the REC terminal.
Speaker (right) Speaker (left)
A message from the laboratory
The ‘L’ in the name ‘L-A1’ stands for laboratory. This is a mark assigned to only the most superbly engineered Kenwood products, and it has
been a mark of pride since our founding. Long years of technological expertise have gone into the making of the L-A1, together with the very
finest of materials, making the L-A1 the very personification of Kenwood quality.
AC outlet for U.K.
Caution
= When using the AC outlet equipped with this
[ea] unit, be sure to consult your dealer for the
corresponding plug.
e External power socket
SWITCHED socket (capacity of 200W):
Plugs for the tuner, cassette tape deck, record player, CD
player and other equipment may be inserted into this socket
so that, if the POWER switch for each of the individual com-
ponents is left on, then the components may be turned on and
off simply by turning on the POWER switch of the main unit.
Under no circumstances should devices totaling over 200W
be connected.

The balance input terminals
TT
The GND (ground) terminal
The GND cord of the record player should be
connected here.
The balance terminals provide a professional
connection method for use at broadcast sta-
tions and in other professional applications.
These terminals may be used for connecting
any equipment with output balance terminals.
To connect your equipment, use either com-
mercially available cables or the Canon ca-
bles that come with your equipment. The end
of the Canon cable without a lock switch is the
end which should be connected to the input
terminal (i.e., balance terminal) of the am-
plifier.
To remove the input terminal from the am-
plifier, press the terminal release lever while
removing the plug.
b=
¢
Insert
the
connecting
cords
firmly
into
their
sockets.
Inserting
these
cords
loosely
may
result
in
noise
or
the
loss
of
sound
altogether.
e
When
inserting
or
removing
the
connecting
cords,
aiways
be
sure
to
first
remove
the
power
cord
from
its
socket.
Inserting
of
removing
the
connection
cords
with
the
power
cord
in
its
socket
may
result
in
the
faulty
operation
of
or
damage
to
the
amplifier.
¢
Donot
connect
any
equipment
with
specified
power
requirements
in
excess
of
the
maximum
power
displayed
above
the
socket
on
the rear
of
the
unit.
How to connect the speakers
Connect the speakers in such a way that the core of the wire does not come into contact with any
terminal other than the speaker terminal.
Prepare the wire for Loosen the
é Ei Insert the speaker
connection. terminal cap.
EB Tighten the
wire.
terminal cap.
20mm
= a / my, (SLI
ae.
g
X SX
(Remove the covering to
expose the core of the
wire.)
Speaker impedance
Use speakers with an impedance from 4 to 16 Q. Under no circumstances should you use speakers
with an impedance less than 4 Q.
° Crossing the jeft and right terminals, or inserting the plus and minus terminals incorrectly may result in muddled sound
where instruments cannot be heard clearly, or in an unnatural, monotone sound. Please be sure to connect the speaker
wires correctly.
¢ Do not cross the plus and minus (+ or -) or left and right (L or R) terminals when connecting the speaker cords.

Names of parts
ON/STAND BY indicator VOLUME CONTROL knob
Pressing the POWER key
causes this indicator to
flash for approximately 5
seconds, after which it
enters the ON state
Remote control Spotlight
signal detector
SOURCE indicator
The red indicator lights up in
INPUT mode;
The orange indicator lights up in
REC OUT mode;
When all indicators are off, the
amplifier is in REC OUT OFF
mode, and no recording may be
done.
Vvouwume| conTRoL
PHONES jack MUTING
key / indicator
INPUT/REC OUT switching
key / REC OUT indicator
POWER key SPEAKERS OFF
key / indicator
CARTRIDGE MM/MC key
/ MC indicator
SOURCE selector knob
A message from the laboratory
Class A operation of the driver stage
The power amplification stage of most amplifiers have class B operation. But in the Kenwood L-A1, in order to fully drive the finai transistors, we've designed the
previous drive stage to have class A operation even under a load of only 4 Q. This reduces the actual amount of distortion in the power amplification stage to levels
never before realized, and allows you to enjoy clear, dynamic sound like never before.
Stand by mode of POWER switch
When the power cord of this system is plugged
into an AC outlet, the STAND BY indicator lights up
regardless of the ON/OFF setting of the POWER
switch. This indicates that a small amount of
current is being supplied to the unit to back up
the memory contents. This mode is referred to as
the Stand By mode. While the STAND BY indicator
is lit, the power of the system can be switched
ON/OFF from the remote control unit.
Speaker protection circuits
When the ON/STAND BY indicator begins flashing
rapidly, it means that the plus (+) and minus (-)
polarity of the speakers has been short-circuited.
If this happens, press the POWER key to turn off
the power, reverse the speaker connections, and
press the POWER key to turn on the power once
again. The amplifier should then return to normal
operation.
10