INTEGRATED AMPLIFIER
L-550AXII
Owner`s Manual
Contents
Precautions ············································································································· 1
Features of This Unit ································································································ 2
Names and Functions ······························································································ 4
Connections ·········································································································· 12
Operations ············································································································· 16
How to use Remote Control ·················································································· 18
Block Diagram ······································································································· 20
Specifications ········································································································ 21
Before Asking for Repair Services ·········································································· 22
INTEGRATED AMPLIFIER L-550AX
Ⅱ
Precautions
Installation place
This unit shall be installed in a well-ventilated and effectively
heat-released place because this unit is an A-class amplifier
and generates considerable heat.
Especially, installation of this unit where direct sunlight is
present, where the temperature rises excessively high such
as close to a heater, or where it is humid or dusty may cause
a malfunction even if heat is efficiently released. Therefore, do
not install this unit in such places.
Ventilation holes
The ventilation holes on the top and bottom boards of this
product must not be blocked because this unit is an A-class
amplifier and generates considerable heat. If the amplifier is
installed on a rack or the like, secure ample space for cooling
and leave the door open. Do not pile up other things on the
amplifier and never put articles on it. Failure to observe this
may cause a malfunction.
Note:
For heat dispersal, do not install this equipment in a confined
space such as a book case or similar unit.
* Note
* *
*
Wall
Cautions in connecting speakers
When making speaker system connections, exercise extra
care not to short-circuit between ! and @ of the speaker
terminals and speaker input terminals of this unit.
If a large signal is applied to the amplifier with its circuit left
short-circuited, a large current may be passed through the
output circuit and cause a malfunction.
The sound is not generated shortly after
the power supply is turned on.
This amplifier is equipped with a time muting circuit in order
to separate the output circuit. Therefore, no sound will be
generated shortly after the power supply is turned on.
If the volume control is set to a high sound level before the
time muting circuit is canceled, a large sound is suddenly
generated. Please be advised that the volume control shall be
set to a low level at first and adjusted after the sound comes
out of the speakers.
Protection circuit
This product is equipped with a protection circuit that is ac-
tivated upon detection of overcurrent, abnormally high tem-
perature, and DC drift to protect the amplifier and speakers.
When the protection circuit is activated, the output to the
speaker terminal is shut off and the standby indicator blinks
to show that this unit is in the muting state. If the protection
circuit is frequently activated even when disconnecting the
AC plug from the wall outlet, waiting for a certain time, con-
necting the plug to the wall outlet again, and turning on the
power again, please consult your dealer.
Precautions in connecting with other
components
When connecting this unit to input devices such as a CD play-
er, an SACD player, a D/A converter, a tuner, and a recorder,
be sure to turn off the power of this unit and all other con-
nected devices. Failure to observe this may generate a strong
noise resulting in speaker damage or cause a malfunction.
The pin-plug to be inserted in each input terminal of this unit
shall be pushed in firmly. If the grounding terminal is inade-
quately connected, noises including hum may be generated,
resulting in an adverse S/N ratio.
Batteries
Caution: Batteries used for the remote control shall not be
exposed to excessive heat such as sunshine, fire or the like.
Repair and adjustment
When repairs or adjustments are needed, please ask the
dealer where you bought the unit.
Cleaning
For cleaning, use a piece of soft cloth to wipe the unit such as
cleaning cloth. When the dirt is hard to remove, use a small
amount of neutral detergent to wipe, and then wipe the unit
with dry cloth. Do not use a solvent like benzine or thinner
because such a substance can damage the exterior.
1
Features of This Unit
New LECUA1000 — LUXMAN Electric
Controlled Ultimate Attenuator 1000
New LECUA1000, which is the integration of an amplifier cir-
cuit and a high-precision attenuator by electrically-controlled
fixed resistance switcheovers is mounted. Further fine sound
volume adjustable without deterioration of sound quality from
0 dB through −87 dB
ODNF — Only Distortion Negative
Feedback —
The amplification feedback circuit that has acquired the high-
speed primary slew rate and ultra-wide bandwidth by feeding
back only distortion components generated during amplifica-
tion to maintain the pure sound quality of the main-amplifier
that is almost non-feedback.
The newest version, 4.0, has achieved the low impedance
and high S/N ratio of the transmission circuit thanks to paral-
lelized first stage and Darlington-connected second stage of
the amplification circuit. In addition, the input stages of the er-
ror detection circuit are parallelized to moderate the distortion
characteristic and to eliminate noise.
Parallel push-pull output stages
Parallel push-pull structure of bipolar transistors.
Pure class A rated output 20 W+20 W (8Ω).
High-inertia power supply
High-inertia power supply circuit that combines a large-ca-
pacity EI-core-type power transformer with original 10,000 μF
× 4 capacitor blocks.
Parallel speaker relays
This unit is equipped with 2 large parallel speaker relays with
a low resistance value to reduce the impedance of the speak-
er output lines.
Beeline construction
Newly designed beeline construction makes the audio input
signals to be conveyed via the optimum and shortest route to
the speaker output.
Selector switch IC
Selector switch IC of high sound quality, which is used in the
top-end control amplifier, C-900u, improves the separation
and crosstalk performances.
Schottky barrier diode
Application of Schottky barrier diode manufactured by Nihon
Inter Electronics Corporation that has less switching noises
and higher conversion efficiency to the DC voltage for the
power supply rectifier circuit.
LUXMAN’s original OFC wires
Our original OFC wires are used in the internal wiring to
achieve smooth signal transmission thanks to the spiral wrap
shielding on each core and the non-plating process on the
core wire.
2
INTEGRATED AMPLIFIER L-550AX
Ⅱ
Round pattern board
After careful consideration of delicate audio signal flow, a
round pattern board has been applied to achieve smooth sig-
nal transmission.
Phono amplifier
This unit is equipped with a phono amplifier that is compat-
ible with the MM/MC cartridge to achieve analog record re-
production in a high-grade level without adding a dedicated
phono amplifier.
Separate function
This unit is equipped with a separate switch to separate the
pre-amplifier and power-amplifier each other that enables the
bi-amp connection adding a power-amplifier and the coexis-
tence with an AV system.
Loopless chassis structure
This unit consists of the independent construction of a
loopless chassis to eliminate increased ground impedance
caused by chassis current.
Large type speaker terminals
Speaker terminals (A and B systems) of inline layout (with
same characteristics for right and left), which is compatible
with Y lugs to enable easy connection with extra-thick speak-
er cables.
Headphone output terminal
This terminal allows you to casually enjoy sound with head-
phones.
Needle-type meter
This unit is equipped with needle-type meters lighted with
LED, which improves the visibility in the listening room.
Aluminum remote control
The high-grade remote control, which is encased in alumi-
num, can control applicable CD/SACD players as well.
18 mm pitch RCA terminal
Introduction of 18 mm pitch all RCA input/output terminals
allows even a high-performance line cable with large plug to
be connected.
3
Names and Functions
891011121314151617
5 6 7
1 2 43
Front panel
1. Operation switch (OPERATION)
2. Operation indicator (OPERATION)
Toggles the power on and off. When wiring or connection is
performed, be sure to turn off this switch.
Blinks in the time of muting mode when the operation
switch is turned on and lights up when the operation state
is activated afterward. This indicator blinks when the unit is
in the muting mode or when the volume is adjusted with the
remote control.
3. Input selector (INPUT SELECTOR)
Selects an input device from the devices such as a CD play-
er, an SACD player, a D/A converter, and a tuner connected
to each input terminal.
The input selector has 6 positions consisting of LINE-4,
LINE-3, LINE-2, LINE-1, BAL LINE, and PHONO from left
to right that correspond to each input terminal on the rear
panel. Rotate the knob to light the input indicator of the
input device to be selected.
4. Input indicator
Lights up at the input device selected with the input selector
or remote control.
4
INTEGRATED AMPLIFIER L-550AX
Ⅱ
5. Display window
Displays the operation status of this unit.
This window is composed of 7 indicators and 2 power me-
ters.
6. Remote sensor (REMOTE)
Receives signals from the accessory remote control.
7. Volume control (VOLUME CONTROL)
Adjusts the sound volume. Sound is not generated when
this control is rotated counterclockwise to the end, and
then, the sound volume gradually becomes higher when the
control is rotated clockwise as follows: mute → –87 dB →
–86 dB → ...... → 0 dB in steps of 1 dB.
8. Headphone jack (PHONES)
Insert the headphone plug into this output jack. Even when
the plug is inserted, signals to the speaker output terminal
are not interrupted. Accordingly, to listen to sound with only
use of headphones, set the speaker selector to “OFF”.
9. Separate switch (SEPARATE)
Separates the pre-amplifier and main-amplifier each other.
off (separate indicator off):
Uses this unit as a normal integrated amplifier.
on (separate indicator on):
Feeds external signals from the MAIN IN terminal on
the rear panel to the main-amplifier section.
• This switch toggles the separate on and off.
The separate indicator lights up when the separate switch
is on.
When the separate switch is set to on, the volume control
of this unit cannot adjust the volume of the speakers con-
nected to this unit. Volume adjustment shall be performed
at the input device side such as a control amplifier con-
nected to the MAIN IN terminal.
Entry of direct output into the MAIN IN terminal from a CD
player or other devices that cannot adjust sound volume
always provides full power and accordingly there is a risk
of speaker damage.
For such input devices, be sure to use a control amplifier
equipped with the sound volume adjustment function as a
relay, generate sound through the speakers with volume
lowered, and adjust the volume to your favorite level.
When arranging the wiring, be sure to turn off the power
of this unit.
5
Names and Functions
891011121314151617
5 6 7
1 2 43
Front panel
10. Line straight switch (LINE STRAIGHT)
Enhances the purity of the sound quality by bypassing the
balance control circuit, tone control circuit, or the like.
off (line straight indicator off): Line straight off/bypass off
on (line straight indicator on): Line straight on/bypass on
• This switch toggles the line straight on and off.
The line straight indicator lights up when the line straight
switch is set to on.
When the line straight switch is set to on, the balance con-
trol, tone control, subsonic, monaural and loudness cannot
be adjusted and the mode selector does not function.
11. Balance control (BALANCE)
Adjusts the balance of sound volume between right and left
channels.
Rotating this control counterclockwise makes the left sound
volume enhanced, and rotating the switch clockwise makes
the right sound volume enhanced. This control shall be set
to the center position under normal conditions, and rotated
to make adjustment if necessary.
When the line straight switch is set to on, this switch does
not function.
12. Tone control for treble
TONE CONTROL (TREBLE)
Controls the frequency characteristics of the high-frequen-
cy range.
When this control is set to the center position, flat frequency
characteristic is obtained. Rotating this control clockwise
makes the high-frequency range enhanced, and rotating
this control counterclockwise makes the high-frequency
range attenuated.
When the line straight switch is set to on, this switch does
not function.
6
INTEGRATED AMPLIFIER L-550AX
Ⅱ
13. Tone control for bass
TONE CONTROL (BASS)
Controls the frequency characteristics of the low-frequency
range.
When this control is set to the center position, flat frequency
characteristic is obtained. Rotating this control clockwise
causes the low-frequency range to be enhanced, and rotat-
ing this control counterclockwise causes the low-frequency
range to be attenuated.
When the line straight switch is set to on, this switch does
not function.
14. Speaker selector (SPEAKERS)
Selects either of 2 speaker systems, A or B, located at the
rear panel.
OFF: Set to off when using headphones. No sound is
generated from any speakers.
A (center): Selects the A system speaker terminals.
B: Selects the B system speaker terminals.
A+B: Simultaneously activates both A and B system
speakers. When both speaker terminals are si-
multaneously used, select speakers with imped-
ance of 8 ohms or more because both output
terminals are connected in parallel.
15. Recording switch (REC OUT)
Sends recording signals to the recorder connected to this
unit.
OFF: Does not send recording signals to the record-
er output terminals on the rear panel.
When not using the recorder, set the recording
switch to OFF.
ON: Selects an input source to be recorded with
the input selector and sends recording signals
to the recorder connected the recorder output
terminals of this unit.
16. Cartridge selection switch
(CARTRIDGE)
Changes the gain level of the equalizer amplifier (amplifier
circuit required to play an analog record).
MC: Selects the MC (moving coil) type cartridge of
low output voltage.
When “MC” is selected during use of the MM
type cartridge, be aware that the sound volume
becomes higher and unbalanced sound without
high frequencies is generated owing to the im-
pedance.
MM: Selects the MM (moving magnet) type cartridge
of high output voltage.
17. Monitor switch (MONITOR)
Toggles between use and nonuse of the monitor input ter-
minals (MONITOR) on the rear panel.
on (monitor indicator on):
Enables to reproduce the data from the recorder.
off (monitor indicator off):
Enables to reproduce the signals from the source se-
lected with the input selector.
• This switch toggles the monitor on and off.
The monitor indicator lights up when the monitor switch
is on.
7
Names and Functions
5
6
2
97 8
2
1 43
Display window
1. Monitor indicator (MONITOR)
Lights up when the monitor switch is on.
2. Power meters
The left meter reads the output of the L channel, and the
right meter reads the output of the R channel. The meters
read the level in decibels.
The meters light when the power is on.
3. Subsonic indicator (SUBSONIC)
Lights up when the subsonic switch is on.
4. Monaural indicator (MONO)
Lights up when the monaural switch is on.
The subsonic, monaural and loudness can be toggled only
from the accessory remote control (RA-17A).
8
INTEGRATED AMPLIFIER L-550AX
Ⅱ
5. Standby indicator (STAND BY)
Lights up when the AC plug is plugged into a wall socket
and the operation switch is set to off.
This indicator turns off when the AC plug is disconnected
from the wall socket or the operation switch is set to on.
This indicator blinks when the protection circuit is activated.
6. Remote sensor (REMOTE)
Receives signals from the accessory remote control.
7. Loudness indicator (LOUDNESS)
Lights up when the loudness switch is on.
8. Line straight indicator (LINE STRAIGHT)
Lights up when the line straight switch is on.
When the line straight switch is set to on, the subsonic,
monaural and loudness cannot be adjusted from the ac-
cessory remote control.
When one of these switches is pressed, the line straight
indicator blinks for 3 seconds to show that this unit cannot
be operated.
Adjust the subsonic, monaural or loudness after setting the
line straight switch to off.
9. Separate indicator (SEPARATE)
Lights up when the separate switch is on.
The subsonic, monaural and loudness can be toggled only
from the accessory remote control (RA-17A).
9
Names and Functions
1
9
2 3 4 5
7
8
6
10
Rear panel
1. Signal ground (SIGNAL GROUND)
Is a ground terminal for devices to be connected to this unit.
This terminal is used to reduce noise when other devices
are connected. This terminal is designed not for safety.
2. Phono input terminal (PHONO)
Is an input terminal to connect an analog record player.
Do not connect a CD player or other devices whose output
level is high to this terminal.
Normal playback cannot be achieved due to sound crack.
3. LINE-1, LINE-2, LINE-3, and LINE-4
input terminals (unbalanced)
(LINE-1, LINE-2, LINE-3, and LINE-4)
Are used for high-level signal inputs from a CD player, an
SACD player, a D/A converter, a tuner, a DVD player, a TV,
and other such devices. The input sensitivity is 180 mV, and
the impedance is 47 kΩ. These input terminals offer the
same functions.
4. Recorder input/output terminals (REC)
Connect the audio input/output of a recorder. The audio
input of a recorder is connected to REC OUT, and the audio
output of a recorder is connected to MONITOR.
Do not insert shortpin plugs into REC OUT.
No sound will be generated.
10
INTEGRATED AMPLIFIER L-550AX
Ⅱ
5. Pre-out terminal (PRE OUT)
This terminal is used to obtain the output of the preampli-
fier section. A bi-amp connection can be performed with
a combination of an external power amplifier because this
terminal always provides output regardless of the separate
switch setting.
Do not insert shortpin plugs into PRE OUT.
No sound is generated.
6. Main in terminal (MAIN IN)
Provides input to the main-amplifier section when the
pre-amplifier and main-amplifier are separated by setting
the separate switch to on.
7. Balanced input terminal/INPUT
(BAL LINE)
Are the balanced input terminals of the LINE level for an XLR
connector.
9. AC inlet (AC IN)
Connects the accessory power cable. The power shall be
supplied from a household wall socket.
10. Speaker terminals (SPEAKERS)
Connects a speaker system.
The right speaker terminal shall be connected to the R side,
and the left speaker terminal shall be connected to the L
side in consideration of the polarity.
General type
terminal
8. Phase inverters (PHASE)
Change the phase when the balance input terminal is used.
The phase shall be corresponding to the phase of the input
device.
A: NORMAL position ① GROUND
② COLD (–)
③ HOT (+)
B: INVERT position ① GROUND
② HOT (+)
③ COLD (–)
* It is possible to insert cables from below
as well as from above.
11
Connections
SPEAKER SYSTEM(A
SPEAKER SYSTEM(B
CD/SACD PLAYER
D/A CONVERTER
RECORDER
–+ –+ –+ –+
12
ANALOG PLAYER
L R L R
)
)
INTEGRATED AMPLIFIER L-550AX
Ⅱ
Before Connecting
Before connecting other devices, connect the jack side of
the accessory power cable to the AC inlet of this unit.
When connecting, turn off the power supply of this unit and
the power supplies of auxiliary devices to prevent unex-
pected accidents that may be caused by noise.
How to connect power supply
Use the accessory power cable and insert the AC plug in an
outlet on the wall in the listening room.
How to connect CD player, SACD player,
D/A converter, tuner, or other devices
Connect between the output terminals of a CD player, an
SACD player, a D/A converter, a tuner, or other such input
devices and the LINE-1 input terminals of this unit with 2 (R
and L) pin-plug cables or balanced cables.
For LINE-2, LINE-3, and LINE-4 input terminals, connection
in the same fashion as the LINE-1 terminals provides the
reproduction likewise.
How to connect speakers
Connect the left-channel speaker to the LEFT SPEAKER
terminal of this unit and the right-channel speaker to the
RIGHT SPEAKER terminal.
Securely connect the ! terminal of the speaker system to
the speaker terminal ! (red) of this unit, and the @ terminal
of the speaker system to the speaker terminal @ (black) of
this unit.
If the ! and @ terminals are reversely connected to either
of the right and left speaker systems, the acoustic phases
of the sound reproduced from the right and left speaker
systems are also reversed. In such a case, be aware that
the sound level in the low range will be reduced and the
acoustic stability will worsen, thus failing in normal stereo
playback.
13
Connections
SPEAKER SYSTEM(A
SPEAKER SYSTEM(B
CD/SACD PLAYER
D/A CONVERTER
RECORDER
–+ –+ –+ –+
14
ANALOG PLAYER
L R L R
)
)
INTEGRATED AMPLIFIER L-550AX
Ⅱ
How to connect analog record player
Connect between the output terminals of an analog record
player and the PHONO terminals of this unit with 2 (R and
L) pin-plug cables.
For some types of players, the ground wire from the phono
motor or the tone arm should be connected to the ground
terminal of this unit.
The phono equalizer of this unit uses the MM or MC car-
tridge. If an MC cartridge with low output voltage is used,
set the cartridge selector on the front panel to the MC po-
sition.
When you need not toggle an input source to be record-
ed (especially when a recorder connected to the recorder
output terminals is recording), do not operate this switch.
Do not insert shortpin plugs into REC OUT. No sound is
generated.
When a CD recorder, tape recorder, or other devices are
connected, be aware that the playback sound volume be-
comes low or no sound is generated if the device extreme-
ly decreases the impedance of the line input terminals of
the recorder or causes short-circuit on the line input termi-
nals when the recording switch is set to on.
The output from an analog record player equipped with a
phono equalizer or from an independent phono equalizer
shall be connected to the line input terminals of this unit.
How to connect recorder
1. Connection to monitor terminal (playback)
Connect between the line output terminals (LINE OUT) of
a recorder and the monitor terminals of this unit with pin-
plug cables in consideration of L and R. Now, setting the
monitor switch on the front panel or the remote control to
on provides playback.
2. Connection to REC OUT terminal (recording)
When the sound source from the various input devices is
reproduced, which are connected to the PHONO or LINE
terminals of this unit, setting the recording switch provides
the REC OUT terminal with the signal.
Connection between the REC OUT terminal of this unit and
the line input terminals (LINE IN) of the recorder with pin-
plug cables is required for recording on the recorder. After
the connection, you can enjoy listening to the sound from
the speaker system and record the sound at the same time.
These output signals for recording are not affected by the
control functions such as the volume control and tone con-
trol functions.
How to connect PRE OUT/MAIN IN
terminal
Either the pre-amplifier or main-amplifier can be separately
used.
When the pre-amplifier or main-amplifier is separately used,
set the separate switch on the front panel to on.
When only the pre-amplifier is used, connect the PRE OUT
terminal of this unit to the input terminal of another pow-
er-amplifier, and when only the main-amplifier is used, con-
nect the MAIN IN terminal of this unit to the output terminal
of another power-amplifier.
When this amplifier is used without separating between
pre-amplifier and main-amplifier, set the separate switch
on the front panel to off, or no sound is generated.
Do not insert shortpin plugs into PRE OUT.
No sound is generated.
15
Operations
Before operation
1. Ensure that the connections are correctly performed.
(Normal playback cannot be achieved with wrong con-
nections of R, L, !, or @)
2. When the power is toggled between on and off or the
input selector is changed over, set the volume control to
the minimum position in advance.
Playback procedure
1. Press the operation switch to turn on the switch after
ensuring that the volume control is set to the minimum
position.
2. Select a source to be reproduced with the input selector.
3. Adjust the sound level with the volume control.
4. Operate the line straight switch, balance control, and
tone control according to the reproduced source.
How to operate line straight switch
The line straight switch is used to play sound with the short-
est signaling route for enhancing the purity of the source
selected with the input selector. When this switch is set to
on, the balance control, tone control, subsonic, monaural
and loudness are bypassed.
How to operate balance control
The balance control allows users to adjust the balance of
sound volume between right and left channels.
When the balance adjustment is not required, the balance
control is set to the center position.
How to operate the tone control
This unit has the tone control function for the low-frequency
and high-frequency ranges.
The low-frequency range type works in the 300 Hz or lower.
The tone control is set to flat frequency characteristics at
the center position. Rotating the control clockwise makes
the low-frequency range enhanced, and rotating the control
counterclockwise makes the low-frequency range attenu-
ated.
The high-frequency range type works in the 3 kHz or more.
The tone control is set to flat frequency characteristics at
the center position. Rotating the control clockwise makes
the high–frequency range enhanced, and rotating the con-
trol counterclockwise makes the high-frequency range at-
tenuated.
For both the low-frequency and high-frequency ranges, the
right and left channels interlockingly function.
When the line straight switch is set to on, the tone control
does not function.
How to record a source
1. Select a source to be recorded with the input selector.
2. Set the recording switch to on.
3. Play the source to be recorded and set the recorder to
the recording state.
* Operation of the tone control or balance control does not
affect the recording signals.
16
When the line straight switch is set to on, the balance con-
trol does not function.
INTEGRATED AMPLIFIER L-550AX
Ⅱ
Procedure of timer-controlled recording
1. Turn on the operation switch to activate this unit.
2. Select a source to be recorded under timer control with
the input selector.
3. Set the recording switch to on.
4. Perform time setting for start and stop times with your
timer.
5. Refer to the operating instructions of the timer and other
connected devices for further information.
If the volume control is not set to low levels, the source se-
lected with the input selector may be reproduced from the
speakers. Be sure to set the volume control to a low level.
When timer-controlled recording is performed, operations
of the amplifier are the same as regular use.
Procedure of timer-controlled playing
1. Turn on the operation switch to activate this unit.
2. Select a source to be reproduced under timer control
with the input selector.
3. Adjust the volume level with the volume control.
4. Perform time setting for start and stop times with your
timer.
5. Refer to the operating instructions of the timer and other
connected devices for further information.
Memory
This unit stores the following items when the power is off:
Item Default
INPUT Selected source
METER on/off
MONITOR on/off
SUBSONIC on/off
MONO on/off
LOUDNESS on/off
LINE STRAIGHT on/off
SEPARATE on/off
Memory reset
The following operations restore all the settings to the factory
defaults.
(1) Turn off the power of this unit.
(2) Hold down the operation switch on the main unit for 5
seconds or more and press the line straight switch on
the main unit once while holding down the operation
switch, and the power state switches from on to off.
Factory default
Item Default
INPUT LINE-1
METER on
MONITOR off
SUBSONIC off
MONO off
LOUDNESS off
LINE STRAIGHT off
SEPARATE off
17
How to use Remote Control
1
2
4
5
10
3
Remote control (RA-17A)
6
7
8
9
11
1. Operation switch (OPERATION)
Toggles the power on and off.
When wiring or connection is performed, be sure to turn off
this switch.
2. Input selector
(LINE-1, LINE-2, LINE-3, LINE-4, BAL-1,
BAL-2, PHONO, MONITOR)
Selects an input terminal from among the unbalanced in-
put terminals on the rear panel (LINE-1, LINE-2, LINE-3,
LINE-4, PHONO, and MONITOR) or the balanced input ter-
minal (BAL LINE).
* The balanced input terminal (BAL LINE) can be selected by
pressing either of BAL-1 or BAL-2.
3. Monaural switch (MONO)
Mixes the signals from right and left channels. The monaural
indicator lights up when this switch is pressed.
Pressing this button again to turn off the monaural switch
provides regular stereophonic reproduction.
* When the line straight switch is set to on, this switch does
not function.
4. Separate switch (SEPARATE)
Separates the pre-amplifier and main-amplifier section each
other.
off (separate indicator off):
Uses this unit as a normal integrated amplifier.
on (separate indicator on):
Feeds external signals from the MAIN IN terminal on
the rear panel to the main-amplifier section.
• Holding down this switch for 1 second toggles the sepa-
rate switch on and off.
The separate indicator lights up when the separate switch
is on.
5. Mute switch (MUTE)
Activates the mute function and blinks the power-on indica-
tor. No sound generated.
Pressing this button again sets the mute function to off.
6. Meter switch (METER)
Turns off the meter lights.
Pressing this switch again turns on the meter lights again.
18
INTEGRATED AMPLIFIER L-550AX
Ⅱ
7. Subsonic switch (SUBSONIC)
approx. 5 meters
Cuts ultra-low frequencies out of audible range to pre-
vent ultra-low range noise from adversely affecting audible
range. This function is significantly effective especially when
an analog record is warped or a woofer is shaking owing to
ultra-low range vibration.
• This switch toggles the subsonic on and off.
The subsonic indicator lights up when the subsonic switch
is on.
* When the line straight switch is set to on, this switch does
not function.
8. Loudness switch (LOUDNESS)
Corrects the characteristics of human ears that causes dif-
ficulty in listening to low-pitched and high-piched sounds
when the sound volume is low.
• This switch toggles the loudness on and off.
The loudness indicator lights up when the loudness switch
is on.
* When the line straight switch is set to on, this switch does
not function.
11. Volume control switches
(VOLUME, i, o)
Adjusts the sound volume.
• Pressing i increases the sound volume in steps of 1 dB.
• Pressing o decreases the sound volume in steps of 1 dB.
Remote control
The remote control shall be aimed at the remote sensor of
this unit within the specified angle range shown in the illus-
tration.
30°30°
Effective distance:
9. Line straight switch (LINE STRAIGHT)
Enhances the purity of the sound quality by bypassing the
balance control circuit, tone control circuit, or the like.
off (line straight indicator off): Line straight off/bypass off
on (line straight indicator on): Line straight on/bypass on
• This switch toggles the line straight on and off.
The line straight indicator lights up when the line straight
switch is set to on.
10. CD/SACD player operation switch
(CD/SACD PLAYER)
This switch is used to control the corresponding CD/SACD
players.
The corresponding CD/SACD players are the following
10models: D-08u, D-06u, D-05u, D-08, D-06, D-05, D-10,
D-7, D-600, and D-700S as of April 2016.
Dry cell
[How to load dry cells]
1. Put your finger on the battery cover claw on the rear of the
remote control, and slide the cover downward to open it.
2. Put 2 AAA batteries in the battery case as shown in the illus-
tration.
3. Close the battery cover.
* When the batteries start to lose power, the effective dis-
tance becomes shorter or the unit does not function even
though the switch is pressed. In such a case, both of the
batteries should be replaced with new ones at the same
time.
* If the remote control is not used for a long time, the batter-
ies should be removed from the case.
19
Block Diagram
LIN
PHO
LIN
LIN
LIN
EC OUT
PRE OUT
MUTE
Pre
amp
1dB
×11step
11dB
×8step
LECUA-1 LECUA-2
Buffer
SUBSONIC
PRE OUT
Phones
B - Speakers
A - Speakers
MUTE
amp
Meter
For EQ. , TC. Pre amp
For Protector
FUSE
RECTIFIER
Backup Transformer
REG.
-computer
For
DC.
OC.
Pre
amp
1dB
×11step
LECUA-2
11dB
×8step
LECUA-1
+B1
-B1
Protector
TEMP.
Speaker selector /
FUSE
AC RELAY
Main Transformer
RECTIFIER RECTIFIER RECTIFIER RECTIFIER
REG. REG.
B1-L
B1-R
B2-L
B2-R
Buffer
For Main Amp
For Driver
STRAIGHT
straight
MONITOR
INPUT
SELECTOR
EQ
Tone
T
STRAIGH
Control
RIAA
MONO
-B2
Tone
Control
straight
+B2
MUTE
-B2
REG. B2
+B2
SEPERATE
Cartridge/Rec Out/Speakers
-com
LED
Monitor/Line Straight/Separate
Remote
REC OUT
SELECTOR
BAL UNBAL
INV.
MM/MC
PHASE INVERT
12
3
Volume/Treble/Bass/Balance
Input Selector
20
NO
E-2
E-1
E-3
E-4
R
MONITOR
MAIN IN
INTEGRATED AMPLIFIER L-550AX
Ⅱ
Specifications
Rated output 20 W+20 W (8 Ω)
40 W+40 W (4 Ω)
Total harmonic distortion 0.007 % (8 Ω, 1 kHz both channels simultaneous drive, line straight on)
0.02 % (8 Ω, 20 to 20 kHz both channels simultaneous drive, line straight on)
Pre-amplifier
Input sensitivity/input impedance
Main-amplifier
Input sensitivity/input impedance
Output voltage REC OUT : 180 mV
S/N ratio PHONO (MM) : 91 dB or more
Frequency response PHONO (MM) : 20 Hz to 20,000 Hz (±0.5 dB, line straight on)
Tone control Max. amount of change BASS : ±8 dB at 100 Hz
Loudness control 100 Hz : +7 dB
Damping factor : 200
Supplied functions • Power meters
Accessories • Remote control RA-17A
Power supply
Power consumption 230 W
Max. external dimensions 440 (W) x 178 (H) x 454 (D) mm
Weight 24.3 kg (main unit only)
PHONO (MM) : 2.5 mV / 47 kΩ
PHONO (MC) : 0.3 mV / 100 Ω
LINE : 180 mV / 47 kΩ
MONITOR : 180 mV / 47 kΩ
BAL. LINE : 180 mV / 55 kΩ
MAIN-IN : 450 mV / 47 kΩ
PRE-OUT : 1 V
(IHF-A correction, 5 mV input)
PHONO (MC) : 75 dB or more
(IHF-A correction, 0.5 mV input)
LINE : 105 dB or more
(IHF-A weighted, input shorted, line straight on)
PHONO (MC) : 20 Hz to 20,000 Hz (±0.5 dB, line straight on)
LINE : 20 Hz to 100,000 Hz (within –3 dB, line straight on)
TREBLE : ±8 dB at 10 kHz
10 kHz : +5 dB
• Balance
• Recording switch
• Monaural switch
• Tone control
• Phone jack
• Phase inverter
• Owner's Manual
• Safety cautions
230V 〜 (50 Hz)
0.5 W (at standby), 170 W (at no input)
(front side knob with 20 mm and rear side terminal with 27 mm included in
depth)
• Speaker selector (A, B)
• Subsonic
• Separate
• Line straight
• Loudness
• Power cable
• 2 pieces of “AAA” batteries
* Specifications and appearance are subject to change without notice.
21
Before Asking for Repair Services
While the unit is used, an unusual phenomenon may be confused as a malfunction for a certain reason. Prior to asking our official sole
distributor of your country for repair services, please check the table below and read the operating instructions for the subsidiary devic-
es. If the cause of the malfunction cannot be identified, please contact your dealer. When we have once accepted your request for
repair services, inspection fees and traveling expenses may be claimed even though the unit is found to be normal.
Problem Cause Solution
No power is supplied even
though the operation switch is
pressed.
No sound is generated. • The volume control is set to the minimum
No sound is generated on one
side.
Humming sound (boon or zzz
noise) is generated.
No effect of tone control or balance control is observed.
The subsonic, monaural or
loudness is not activated.
The lights of the power meters
are not turned on.
The separate switch of the remote control is not activated.
• The power plug is disconnected from the
wall outlet, or it is not completely inserted.
• The power plug is disconnected from the
AC inlet, or it is not inserted completely.
level.
• The input selector is not set to the source to
be reproduced.
• Cable connections are incomplete. • Make cable connections securely.
• The output level of the input device is set to
the minimum position.
• The separate switch is set to on. • Set the separate switch to off.
• The mute switch of the remote control is set
to on.
• The balance control is fully rotated. • The balance control shall be set to the cen-
• The connecting cable is not connected on
one side only.
• The ground side of the pin-plug cable has
no contact with the terminal.
• The ground wire of the analog record player
is not connected.
• Connections or mounting conditions are incomplete between the cartridge and shell,
or between the shell and tone arm of the
analog record player.
• The line straight switch is set to on. • When tone control or balance control is
• The line straight switch is set to on. • When the subsonic, monaural or loudness
• The meter switch is set to off. • Set the meter switch of the remote control
• To prevent incorrect operations, this unit is
designed to toggle the separate on/off by
holding down the separate switch approximately for approx. 1 second.
• Insert the power plug in the wall outlet completely.
• Securely insert the power plug in the AC inlet.
• Rotate the volume control clockwise to adjust the sound volume.
• Set the input selector to the source to be
reproduced.
• Adjust the output level.
• Set the mute switch to off.
ter position under normal conditions.
• Make cable connections securely.
• Make connections securely so that the
ground side of the pin-plug cable can be
connected.
• Connect the ground wire of the analog record player to the GND terminal.
• Connect (or mount) the cartridge, shell, and
tone arm securely.
used, the line straight switch shall be set to
off.
is used, the line straight switch shall be set
to off.
to on.
• Hold down the separate switch of the remote control for approx. 1 second.
22
INTEGRATED AMPLIFIER L-550AX
Ⅱ
MEMO
23
MEMO
24
LUXMAN CORPORATION, JAPAN
1-3-1 Shinyokohama, Kouhoku-ku, Yokohama-shi, Kanagawa 222-0033, Japan
AG00987E52A
Printed in Japan
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