Luxman C-900u User manual

Owner`s Manual
LUXMAN CORPORATION, JAPAN
CONTROL AMPLIFIER
C-900u

Contents
Precautions ············································································································· 1
Features of This Unit································································································ 2
Names and Functions······························································································ 4
Connections ·········································································································· 12
Operations············································································································· 18
How to use Remote Control ·················································································· 20
Block Diagram······································································································· 27
Specifications ········································································································ 30
Before Asking for Repair Services·········································································· 31

CONTROL AMPLIFIER C-900u
1
Precautions
Installation place
Install this unit in a location where good ventilation and heat
radiation is assured.
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.
Note:
For heat dispersal, do not install this equipment in a confined
space such as a book case or similar unit.
Precautions in connecting with other
components
When connecting this unit to input/output devices, be sure to
turn off the power switches of this unit and all other connect-
ed units. Failure to observe this may generate a strong noise
resulting in speaker damage or cause a malfunction.
The pin-plugs to be inserted in the input and output terminals
of this unit shall be pushed in firmly. If the grounding termi-
nal is inadequately connected, noises including hum may be
generated, resulting in an adverse S/N ratio.
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 is generated
shortly after the power supply is turned on.
If the volume control is moved 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 sound comes out
of the speakers.
Batteries
Caution:
Batteries used for remote controller shall not be exposed to
excessive heat such as sunshine, fire or the like.
Repair and adjustment
When repair and adjustments are needed, please ask the
store where you bought the unit.
Cleaning
For cleaning, use a piece of soft cloth to wipe the unit such as
cleaning cloth available on the market. If the unit has become
very dirty, remove the dirt with soft cloth absorbing a small
amount of neutral detergent, and then wipe the unit with dry
cloth. Do not use a solvent like benzine or thinner because
such a substance can often damage the exterior.
* Note
Wall
* *
*

2
Features of This Unit
LECUA1000 — LUXMAN Electric
Controlled Ultimate Attenuator 1000
Application of the system to obtain attenuation by combining
2 fixed resistances connected in series has improved the effi-
ciency of the LECUA1000 attenuator used in C-1000f.
The shortest signaling route has been achieved by the in-
tegrated amplifier circuit thanks to the 3D structure of the
mounting boards.
Controlling LECUA1000 to the level equal to the volume po-
sition detected by a microprocessor has achieved the oper-
ation feeling similar to our conventional sliding-type volume
controls.
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 4-par-
allelized first stage and Darlington-connected second stage
of the amplification circuit.
In addition, the input stages of the error detection circuit are
3-parallelized to improve distortion and noise.
High-inertia power supply
High-inertia power supply circuit that combines a large-ca-
pacity OI-core-type power transformer with customizable
3,300μF × 4 capacitor blocks.
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.
Loopless chassis structure
This unit consists of the independent construction of a
loopless chassis to eliminate increased ground impedance
caused by chassis current.

CONTROL AMPLIFIER C-900u
3
Zoom function
When the ZOOM button on the remote control is pressed, the
current volume level is enlarged on the display.
Dimmer function
The brightness of display window can be switched over in 4
steps.
Peel coat, PCB
Dielectric effect of resist eliminated by using copper foil of
100μm in thickness and gold plating on audio circuit board
instead of using resist.
Input/output terminals
RCA terminal made of copper alloy and XLR terminal manu-
factured by Neutrik.
Remote control (RA-20)
The remote control is encased in aluminum. Tactile switches
will satisfy users with solid click feeling.
Tactile switches will satisfy users with light key touch.
Cast-iron insulator
This unit is equipped with gradation cast-iron insulators that
cuts out unnecessary external vibration and strongly supports
the weight of this unit.
External pre-input terminal
External pre-function capable of switching between external
pre-amplifier and AV amplifier.
Selector relay
Selector relay with high sound quality used in the key point of
Luxman amplifier, which enhances the separation and cross-
talk performances.

4
Names and Functions
1. Operation switch (OPERATION)
Turns this unit from the standby state to operation state.
When the main power switch on the rear panel is turned on
to set this unit to the standby state and this switch is turned
on, this unit is set to the operation state.
2. Operation indicator (OPERATION)
Blinks during warm-up when the operation switch is turned
on and lights up when the operation state is activated af-
terward.
3. Input selector (INPUT SELECTOR)
Selects the unbalanced input terminal or balanced input ter-
minal, both of which are located on the rear panel.
• Input transition by rotating clockwise:
LINE-1→LINE-2→LINE-3→BAL LINE-1→BAL LINE-2→
BAL LINE-3→LINE-1...
• Input transition by rotating counterclockwise:
LINE-1→BAL LINE-3→BAL LINE-2→BAL LINE-1→
LINE-3→LINE-2→LINE-1 …
Factory default: LINE-1
The input/output muting circuit is activated to mute sound
during selecting an input.
4. Display window
Displays the operation status of this unit.
This display window is composed of 8 indicators, input dis-
play, and volume display.
5. Volume control (VOLUME CONTROL)
Adjusts the sound volume.
Sound is not generated when this control is rotated coun-
terclockwise to the end, and then, the sound volume grad-
ually becomes higher when the control is rotated clockwise
as follows: mute→-87 dB→-86 dB→..→0 dB in steps of
1 dB.
678912 1011
51 2 43
Front panel

CONTROL AMPLIFIER C-900u
5
6. External pre switch (EXT PRE)
Input selector switch to select the external pre-input termi-
nal (EXT PRE) on the rear panel
ON: Allows the output signals coming from the pre-ampli-
fier or AV amplifier connected to the external pre-in-
put terminal to be provided directly from the unbal-
anced terminal.
OFF: Enables to reproduce the signals from the source se-
lected with the input selector.
Holding down the switch for approx. 1 second toggles the
external pre switch ON and OFF.
When the external pre switch is set to ON, the external pre
indicator lights up.
When the main power switch is turned off or this unit is
in the standby state, external pre-input signals are always
provided from the unbalanced output terminal regardless of
this switch setting.
The input signals connected to the external pre-input ter-
minal are not provided from the balanced output terminal.
When the external pre switch is set to ON, the volume con-
trol of this unit cannot adjust the sound volume.
Volume adjustment shall be performed at the input device
side such as the pre-amplifier connected to the external
pre-input terminal.
If a device that has no volume adjustment function such as
a CD player is connected to the external pre-input terminal,
the volume control of this unit cannot function, and there-
fore, sudden loud sound may be generated when the exter-
nal pre-input is selected, which may cause hearing loss or
damage to the speakers.
For such input devices, be sure to use a pre-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.
7. Output mode selection switch
(OUTPUT MODE)
Selects an output mode from the following 3 kinds: unbal-
anced output, balanced output, and bi-amplifier output
Every time this switch is pressed, the output changes as
follows: UNBAL→BAL→BI-AMP→UNBAL ...
• Unbalanced output (UNBAL)
Sound comes out from LINE-1 and LINE-2.
• Balanced output (BAL)
Sound comes out from BAL LINE-1 and BAL LINE-2.
• Bi-amplifier output (BI-AMP)
Sound comes out from LINE-1 and LINE-2.
LINE-1 (Lch): LOW (Lch)
LINE-1 (Rch): LOW (Rch)
LINE-2 (Lch): HIGH (Lch)
LINE-2 (Rch): HIGH (Rch)
When the input selector is set to balanced, the bi-amplifier
output cannot be selected.
Change the output mode after setting the input selector to
unbalanced.
Factory default: Unbalanced output (UNBAL) mode
The input/output muting circuit is activated to mute sound
during selecting an output mode.
Every output mode can store preset values, respectively.
Refer to the descriptions about presetting on pages 22 to
25 for presetting.
8. Balance control (BALANCE)
Adjusts the balance of sound volume between right and left
channels.
Rotating this control counterclockwise causes the left sound
volume to be enhanced, and rotating this control clockwise
causes the right sound volume to be enhanced.
This control shall be set to the center position under normal
conditions, and rotated to make adjustment if necessary.
The adjustable value for right/left balance is up to -6 dB for
right and left each.
9. Remote sensor (REMOTE)
Receives signals from the accessory remote control.

6
Names and Functions
10. Tone control for treble
TONE CONTROL (TREBLE)
Controls the frequency characteristics in the high-frequency
range.
When this control is set to the center position, flat frequency
characteristic is obtained. Rotating this control clockwise
causes the high-frequency range to be enhanced, and ro-
tating this control counterclockwise causes the high-fre-
quency range to be attenuated.
This control does not function when the line straight switch
is set to ON.
11. Tone control for bass
TONE CONTROL (BASS)
Controls the frequency characteristics in 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.
This control does not function when the line straight switch
is set to ON.
12. Line straight switch (LINE STRAIGHT)
This switch is used to increase the purity of the sound qual-
ity by bypassing (skipping) the tone control circuit.
Every time this switch is pressed, line straight setting tog-
gles between ON and OFF repeatedly.
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 tone control
and loudness do not function.
678912 1011
51 2 43
Front panel

CONTROL AMPLIFIER C-900u
7

8
Names and Functions
1. Input indicator (IN:)
Displays the input terminal selected with the input selector
or remote control.
2. Volume indicator (VOL:)
Indicates the current volume level in steps of 1 dB.
• “- -“ shows the mute state. No sound is generated.
• The minimum volume level is shown as “–87 dB”, and the
maximum volume level is shown as “0 dB”.
3. Loudness indicator (LOUDNESS)
Lights up when the loudness switch on the remote control
is set to ON.
4. Balance indicator (BAL)
Lights up when the balanced output terminal is selected for
the output mode.
5. Standby indicator (STAND BY)
Lights up when the main power switch on the rear panel is
turned on and the operation switch is turned off.
When the operation switch is turned on or when the main
power switch is turned off, this indicator turns off.
6. Unbalance indicator (UNBAL)
Lights up when the unbalanced output terminal is selected
for the output mode.
7. Remote sensor (REMOTE)
Receives signals from the accessory remote control.
Display window
6 75 9
1
3
2
411108

CONTROL AMPLIFIER C-900u
9
8. Bi-amplifier indicator (BI-AMP)
Lights up when the bi-amplifier output is selected for the
output mode.
9. Balanced phase inversion indicator
(BAL INVERT)
Lights up when the phases of the balanced input and bal-
anced output are inverse against the preset state of this
unit.
10. External pre indicator (EXT PRE)
Lights up when the external pre switch is set to ON.
11. Line straight indicator (LINE STRAIGHT)
Lights up when the line straight switch is set to ON.
When the line straight switch is set to ON, the loudness
function cannot be operated from the accessory remote
control.
If this switch is pressed, the line straight indicator blinks for 3
seconds to show that this operation cannot be performed.
Perform the loudness function after setting the line straight
switch to OFF.
The loudness function can be toggled ON and OFF only with
the accessory remote control (RA-20).

10
Names and Functions
1. Unbalanced input terminals/INPUTS
(LINE-1, LINE-2, LINE-3)
RCA input terminals to receive unbalanced audio signals of
a line level
Connect these terminals to an unbalanced output of an in-
put device such as a CD player with a pin-plug cable.
Incoming audio signals are selected with the input selector
and delivered.
LINE-1, LINE-2, and LINE-3 have the same quality.
2. Unbalanced output terminals/OUTPUTS
(LINE-1, LINE-2)
RCA output terminals to provide unbalanced audio signals
of this unit
Connect these terminals to an unbalanced input of an out-
put device such as a power amplifier with a pin-plug cable.
Audio output signals are selected with the output mode se-
lection switch.
LINE-1 and LINE-2 have the same quality.
Factory default output mode: Unbalanced (UNBAL)
3. External pre-input terminal
(EXT PRE IN)
RCA input terminal to receive output signals from an exter-
nal pre-amplifier or an AV amplifier
Incoming audio signals are provided directly from the unbal-
anced output terminal.
External pre-input signals are not affected by the volume
control of this unit.
4. Remote output terminals
(REMOTE OUT)
If a power amplifier (e.g. M-900u) equipped with a dedicat-
ed remote input terminal is connected to this remote output
terminal with a dedicated remote cable, the power of the
signal-receiving power amplifier can be turned on and off in
conjunction with the operation switch of this unit.
ON signals from the remote output terminals are transmit-
ted in a certain period of time after pressing the operation
switch of this unit. Therefore, the signal-receiving power
amplifier is activated after the elapse of time that consists
of the muting time of the signal-receiving amplifier and this
transmission delay time.
The remote output terminals 1 and 2 can turn on and off 2
units of power amplifiers at the same time.
Refer to the owner’s manual of a signal-receiving power
amplifier for available operation settings of the signal-receiv-
ing power amplifier.
1
6 58
2 3 4
9 7
Rear panel

CONTROL AMPLIFIER C-900u
11
5. Main power switch (MAIN POWER)
Turns this unit to the standby state.
When this switch is set to ON, the standby indicator on the
front panel lights up to show that this unit turns to the stand-
by state.
When this switch is set to OFF, the standby indicator on the
front panel turns off to show that the main power is turned
off.
6. AC inlet (AC IN)
Connects the accessory power cable.
The power shall be supplied from a household wall socket.
7. Balanced output terminals/OUTPUTS
(BAL LINE-1, BAL LINE-2)
XLR connector output terminal to provide balanced audio
signals from this unit
Connect these terminals to a balanced input of an output
device such as a power amplifier with a balanced cable.
Audio output signals are selected with the output mode se-
lection switch.
BAL LINE-1 and BAL LINE-2 have the same quality.
Factory default output mode: Unbalanced (UNBAL)
8. Signal ground (ground terminal)
(SIGNAL GROUND)
Is a ground terminal for devices to be connected to this unit.
This terminal is used not for safety but for noise reduction
when other devices are connected.
9. Balanced input terminals/INPUTS
(BAL LINE-1, BAL LINE-2, BAL LINE-3)
XLR connector input terminal to receive balanced audio sig-
nals of a line level.
Connect these terminals to a balanced output of an input
device such as a CD player with a balanced cable.
Incoming audio signals are selected with the input selector
and delivered.
BAL LINE-1, BAL LINE-2, and BAL LINE-3 have the same
quality.

12
Connections
Normal stereophonic reproduction
CD/SACD PLAYER
L R
L R L R L R
L R L R
POWER AMP 1
POWER AMP 2
L R
L R L R L R
SPEAKER SYSTEM 1
L R
SPEAKER SYSTEM 2
L R
REMOTE REMOTE
CD/SACD PLAYER CD/SACD PLAYER

CONTROL AMPLIFIER C-900u
13
Before Connecting
Before connecting other devices, connect the jack side of the
accessory power cable to the AC inlet of this unit.
Before connection, turn off the main power switch of this
unit and the power of all other connected devices to prevent
unexpected 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 room where the unit will be installed.
How to connect the input terminals to
input devices such as a CD player
Connect between the output terminals of an input device
such as a CD player and the input terminals of this unit with
pin-plug cables or balanced cables.
At this moment, exercise extra care not to conduct wrong
connection between the right and left channels. If the right
and left channels are connected reversely, the localization of
sound images is deteriorated, thus failing in normal stereo
playback.
If pin-plug cables are used, inadequate connection of the
grounding of the cables may generate noises including hum,
resulting in an adverse S/N ratio. Surely insert the connection
plug.
How to connect the output terminals to
output devices such as a power amplifier
Connect between the input terminals of an output device
such as a power amplifier and the output terminals of this unit
with pin-plug cables or balanced cables.
At this moment, exercise extra care not to conduct wrong
connection between the right and left channels. If the right
and left channels are connected reversely, the localization of
sound images is deteriorated, thus failing in normal stereo
playback.
If pin-plug cables are used, inadequate connection of the
grounding of the cables may generate noises including hum,
resulting in an adverse S/N ratio. Surely insert the connection
plug.
How to connect the remote output
terminal to a power amplifier
Connect between the remote input terminal of a power ampli-
fier such as Luxman M-900u and the remote output terminal
of this unit with the dedicated remote cable (no polarity) sup-
plied with the power amplifier.
After this connection, the power of the power amplifier can
be turned on and off in conjunction with the operation switch
of this unit.
Two (2) remote output terminals are available, and both ter-
minals provide the same signals. Use them according to your
taste.
Use the dedicated remote cable only for the connection be-
tween Luxman control amplifiers and Luxman power amplifi-
ers. Connection to such a terminal that the remote output of
this unit is short-circuited may cause a malfunction.
When this unit is connected to an output device, turn off the
main power switch of this unit or turn this unit to the standby
state to protect the amplifier and speakers from excessive
input. Also turn off the power of the input/output devices con-
nected to this unit. After connection, ensure that connections
are appropriately performed and turn this unit and the input/
output devices to the operating state.

14
Connections
Bi-amplifier stereophonic reproduction
POWER AMP
LOW
POWER AMP
HIGH
L R
L-LOW L-HIGHR-LOW R-HIGH
L R L R
SPEAKER SYSTEM
REMOTE
REMOTE
L R
CD/SACD PLAYER CD/SACD PLAYER CD/SACD PLAYER

CONTROL AMPLIFIER C-900u
15
Bi-amplifier stereophonic reproduction
How to connect the input terminals to
input devices such as a CD player
When the output mode is set to the bi-amplifier output, only
the unbalanced input terminal is active as an input terminal of
this unit and no sound comes if the balanced input terminal
is connected.
Connect between the unbalanced output terminal of an input
device such as a CD player and the unbalanced input termi-
nal of this unit with a pin-plug cable.
At this moment, exercise extra care not to conduct wrong
connection between the right and left channels. If the right
and left channels are connected reversely, the localization of
sound images is deteriorated, thus failing in normal stereo
playback.
If the grounding of the pin-plug cables is inadequately con-
nected, noises including hum may be generated, resulting in
an adverse S/N ratio. Surely insert the connection plug.
How to connect the output terminals to
output devices such as a power amplifier
When the output mode is set to the bi-amplifier output, only
the unbalanced output terminal is active as an output terminal
of this unit and no sound comes if the balanced output termi-
nal is connected.
Connect between the unbalanced input terminal of an output
device such as a power amplifier and the unbalanced output
terminal of this unit with a pin-plug cable.
At this connection, exercise extra care not to conduct wrong
connection between right and left channels. If the right and
left channels are connected reversely, the localization of
sound images is deteriorated, thus failing in normal stereo
playback.
If the grounding of the pin-plug cables is inadequately con-
nected, noises including hum may be generated, resulting in
an adverse S/N ratio. Surely insert the connection plug.
The LINE-1 L terminal is provided for low frequency output of
the L channel, and the LINE-2 L terminal is provided for high
frequency output of the L channel. The LINE-1 R terminal is
provided for low frequency output of the R channel, and the
LINE-2 R terminal is provided for high frequency output of the
R channel.
The LINE-2 unbalanced output terminal that is the output for
high frequency can adjust the sound volume of up to ±6 dB
in steps of 1 dB with the preset operation of the supplied
remote control.
How to connect the remote output
terminal to a power amplifier
Connect between the remote input terminal of a power ampli-
fier such as Luxman M-900u and the remote output terminal
of this unit with the dedicated remote cable (no polarity) sup-
plied with the power amplifier.
After this connection, the power of the power amplifier can
be turned on and off in conjunction with the operation switch
of this unit.
Two (2) remote output terminals are available, and both ter-
minals provide the same signals. Use them according to your
taste.
Use the dedicated remote cable only for the connection be-
tween Luxman control amplifiers and Luxman power amplifi-
ers. Connection to such a terminal that the remote output of
this unit is short-circuited may cause a malfunction.
When this unit is connected to an output device, turn off the
main power switch of this unit or turn this unit to the standby
state to protect the amplifier and speakers from excessive
input. Also turn off the power of the input/output devices con-
nected to this unit. After connection, ensure that connections
are appropriately performed and turn this unit and the input/
output devices to the operating state.

16
Connections
External pre reproduction
L R
POWER AMP 1 POWER AMP 2
SPEAKER SYSTEM 1
L R
SPEAKER SYSTEM 2
L R
REMOTE REMOTE
AV AMP/PRE AMP
L R L R

CONTROL AMPLIFIER C-900u
17
External pre reproduction
Connection between external pre-input
terminal and input devices such as an AV
amplifier
When this unit is used through the external pre-input, only the
unbalanced output terminal is active as an output terminal
of this unit and no sound comes from the balanced output
terminal.
When the main power switch is turned off or this unit is in the
standby state, external pre -input signals are always provided
from the unbalanced output terminal regardless of the exter-
nal pre switch setting.
Connect between the pre-out terminal of an input device
such as an AV amplifier or a pre-amplifier and the external
pre-input terminal of this unit with a pin-plug cable.
At this moment, exercise extra care not to conduct wrong
connection between the right and left channels. If the right
and left channels are connected reversely, the localization of
sound images is deteriorated, thus failing in normal stereo
playback.
If the grounding of the pin-plug cables is inadequately con-
nected, noises including hum may be generated, resulting in
an adverse S/N ratio. Surely insert the connection plug.
When the external pre switch is set to ON, the volume control
of this unit cannot adjust the sound volume.
Volume adjustment shall be performed at the input device
side such as an AV amplifier and a pre-amplifier connected to
the external pre-input terminal.
If a device that has no volume adjustment function such as
a CD player is connected to the external pre-input terminal,
the volume control of this unit cannot function, and there-
fore, sudden loud sound may be generated when the external
pre-input is selected, which may cause hearing loss or dam-
age to the speakers.
For such input devices, be sure to use a pre-amplifier
equipped with the sound volume adjustment function as a
relay, generate sound through the speakers with volume low-
ered, and adjust the volume to your favorite level.

18
Operations
Before operation
1. Ensure that the connections are correctly performed.
(Normal playback cannot be achieved with wrong con-
nections of R and L.)
2. When the power is turned on or 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, tone
control, and the like 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 tone control 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 characteristic at the
center position. Rotating the control clockwise causes the
low–frequency range to be enhanced, and rotating the con-
trol counterclockwise causes the low-frequency range to be
attenuated.
The high-frequency range type works in the 3 kHz or higher.
The tone control is set to flat frequency characteristic at
the center position. Rotating the control clockwise causes
the high–frequency range to be enhanced, and rotating the
control counterclockwise causes the high-frequency range
to be attenuated.
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.