R
LTO
OWNER'S MANUAL
D1/D2/D3/D4
PROFESSIONAL POWER AMPLIFIERS
www.altoproaudio.com
Version 1.3 SEPTEMBER 2007
English
IMPORTANT SAFETY INSTRUCTION
CAUTION
RISK OFELECTRIC SHOCK
DO NOTOPEN
TO REDUCE THE RISK OF ELECTRIC SHOCK
PLEASE DO NOT REMOVE THE COVER OR
THE BACK PANEL OF THIS EQUIPMENT.
THERE ARE NO PARTS NEEDED BY USER
INSIDE THE EQUIPMENT. FOR SERVICE,
PLEASE CONTACT QUALIFIED SERVICE
CENTERS.
This symbol, wherever used, alerts you to the
presence of un insulated and dangerous voltages
within the product enclosure. These are voltages that
may be sufficient to constitute the risk of electric
shock or death.
This symbol, wherever used, alerts you to
important operating and maintenance instructions.
Please read.
Protective Ground Terminal
AC mains (Alternating Current)
Hazardous Live Terminal
ON: Denotes the product is turned on.
OFF: Denotes the product is turned off.
CAUTION
Describes precautions that should be observed to
prevent damage to the product.
1.
Read this Manual carefully before operation.
Keep this Manual in a safe place.
2.
Be aware of all warnings reported
3.
with this symbol.
4.
Keep this Equipment away from water and
moisture.
5.
Clean it only with dry cloth. Do not use
solvent or other chemicals.
6.
Do not damp or cover any cooling opening.
Install the equipment only in accordance with
the Manufacturer's instructions.
Power Cords are designed for your safety. Do
7.
not remove Ground connections! If the plug
does not fit your AC outlet, seek advice from
a qualified electrician. Protect the power
cord and plug from any physical stress to
avoid risk of electric shock. Do not place
heavy objects on the power cord. This could
cause electric shock or fire.
Unplug this equipment when unused for long
8.
periods of time or during a storm.
Refer all service to qualified service personnel
9.
only. Do not perform any servicing other than
those instructions contained within the
User's Manual.
To prevent fire and damage to the product,
10.
use only the recommended fuse type as
indicated in this manual. Do not short circuit
the fuse holder. Before replacing the fuse,
make sure that the product is OFF and
disconnected from the AC outlet.
WARNING
To reduce the risk of electric shock
and fire, do not expose this equipment
to moisture or rain.
Dispose of this product should
notbeplacedinmunicipalwaste
and should be separate collection.
MovethisEquipmentonlywithacart,
11.
stand, tripod, or bracket,
specified by the
manufacturer, or
sold with the
Equipment. When
a cart is used, use
caution when
moving the cart /
equipment
combination to
avoid possible
injury from tip over.
12.
Permanent hearing loss may be caused by
exposure to \ extremely high noise levels.
The US. Government's Occupational Safety
and Health Administration (OSHA) has
specified the permissible exposure to noise
level.
These are shown in the following chart:
HOURS X DAY
8
6
4
3
2
1,5
1
0,5
0,25 or less
According to OSHA, an exposure to high SPL in
excess of these limits may result in the loss of
heat. To avoid the potential damage of heat, it is
recommended that Personnel exposed to
equipment capable of generating high SPL use
hearing protection while such equipment is
under operation.
The apparatus shall be connected to a mains
socket outlet with a protective earthing
connection.
The mains plug or an appliance coupler is used
as the disconnect device, the disconnect device
shall remain readily operable.
SPL
EXAMPLE
Small gig
90
train
92
Subway train
95
High level desktop monitors
97
Classic music concert
100
102
105
110
115
Rock concert
IN THIS MANUAL:
1. INTRODUCTION..............................................................................
2. FEATURES.....................................................................................
1
1
3. CONTROL ELEMENTS...................................................................5
4. OPERATION...................................................................................8
5. BLOCK DIAGRAM........................................................................11
6. TECHNICAL SPECIFICATION ........................................................12
7. WARRANTY.................................................................................13
1. INTRODUCTION
Thank you for expressing your confidence in LTO products by purchasing one or
more of our D series power amplifiers. The D range includes D1, D2, D3 and D4.
There are 2 channels for the D1/D3, and 4 channels for D2/D4. All models are
rugged, 2 rack-unit amplifiers fan-cooled. They provide a lot of power and a high value
performance. They are all designed for heavy-duty application and they all can drive
4 ohm loads for long periods without overheating. Therefore they are suited to drive
subwoofers with a minimum load of 8 ohm when working in Bridge Mode.
Enjoy your D amplifier and make sure to read this manual carefully before operation!
2. FEATURES
Illuminated Power Switch
Automatic Clip-limiter circuit
Switchable low-frequency filter at 30 Hz
Operating Mode is: Stereo, Parallel or Bridge
Balanced Combo input connectors
Output connectors are speak-on jacks and binding post terminals
Low-noise, variable speed fan
Front panel LED indicating Signal and Clipping and Protection Status
Class D technology, switch power, light weight and high power
Manufactured under TS16949, ISO14001 certified management system
1
SPOTLIGHT
SG CLIPPROT SG CL P PROT
20
0
18
8
2
22
1
1
24
24
26
1
CH1
SG CLIPPROT SG CL P PROT SIGCL P PROT IG CLIP PROT
18
1
1
CH1
SG CLP PROT SIG CL P PROT
16
1
CH1
26
1
28306
28
( B)
(dB)
CH2
0
20
0
20
8
18
2
22
22
1
16
24
4
26
1
28306
( B)
CH2
8
22
16
24
26
12
2806
(dB)
CH2
4
26
6
12
8
8306
(dB
dB)
CH3
CH4
0
20
1
22
4
6
28306
dB)
D1
500W 2
D1
D2
20
18
22
6
24
6
2
8306
dB)
500W 4
D2
D3
750W 2
SIG CL P PROT SIG CLIP PROT SG CLIP PROT SG CL P PROT
20
20
1
22
16
12
28306
dB)
CH1
20
18
18
22
2
6
16
4
24
6
2
CH2
24
6
26
1
8306
28
dB)
( B)
CH3
CH4
30
D3
D4
0
8
22
16
24
26
1
2806
(dB)
750W 4
D4
2
HOOK
STEREO MODE
UP
D1
1
1
4
4
1
1
8
0W
In this mode 2 independent channels are sent to 2 separate speakers.
HOOK
PARALLEL MODE
UP
D1
0
One mono signal is input to CH A or CH B of the D series amplifier and then
output to 2 separate speakers. Each speaker volume can be set separately.
3
HOOK
BRIDGE MODE
UP
D1
T
1
6
4
4
1
8
8
0W
The stereo or mono signal input to CH A and CH B is combined on the BRIDGE
MONO connector. Only CH A Gain control is active. The power at the output will
be combined power of the two channels.
HOOK
STEREO BIAMP
UP
T
4
4
1
8
8
T
4
4
1
8
8
)
D1
D1
ThisapplicationisonlyforD1orD3.FortheD2orD4,ithasfourchannelssoonly
use one amplifier. The Main Mix signal is routed into an electronic crossover. CH A drives
the woofer and CH B drives the high frequency driver in a 2-way enclosure.
4
SPOTLIGHT
3. CONTROL ELEMENTS
Front Panel:
1 POWER SWITCH & INDICATOR LED
It powers the D amplifier ON and OFF. When the D amplifier is turned on the
power switch illuminates blue.
2 SIGNAL LED
This LED will light up green when the signal at the output is at least -20 dB.
3CLIPLED
This LED will flash when distortion reaches a level of 0.5%, Turn the relative
GAIN control down so that the CLIP LEDs only flash occasionally.
4 PROTECTION LED
It will light up when the unit is in Protection Mode due to short circuit, low
impedance load or other causes.
5GAINCONTROLS
These controls are used to adjust the output signal level.
6 COOLING VENTS
Allow air circulation from front to back of the amplifier.
SIG CL P PROT SG CLIP PROT SG C IP PROT SIG CL P PROT
0
1
2
6
24
2
28306
dB)
CH1
2
1
16
6
1
CH2
1
2
22
16
16
24
24
26
26
1
12
806
2806
dB)
(dB
CH3
CH4
3
2
SIG CLIP PROT SIG CL P PROT SG CLIP PROT SIG CLIP PROT
20
20
18
18
22
1
16
24
26
12
12
28
6
(dB)
CH1
CH2
30
20
18
22
22
1
24
26
28306
dB)
16
24
26
12
12
28
6
6
(dB)
CH3
CH4
30
5
D2
22
4
6
2806
dB)
1
4
20
18
22
24
6
28
dB)
30
6
500W 4
5
SPOTLIGHT
3. CONTROL ELEMENTS
Rear Panel:
7 CIRCUIT BREAKER
This is an electronic fuse for protecting the unit from possible damage. When the
unit is overloaded or the temperature inside the unit is too high, this push-type
button will spring out and disconnect the power supply. Push the Breaker to restore
normal working conditions.
8 IEC socket for AC power cable
Connect the supplied main cord. Do not insert the power cord into the D amplifier
and into the AC Outlet until voltage has been correctly set.
9 COMBO BALANCED INPUT CONNECTORS
Each Channel features balanced combo connector that used to input the signal to
the amplifier.
10 SPEAKON OUTPUTS
These connectors are specifically designed to connect high power speakers. The
correct polarity is secured automatically, they prevent shock hazard and they lock-in
securely.
11 BINDING POST OUTPUTS
Please make sure to respect the speaker polarity when using binding post.
Caution:
Turn off the unit before connecting an audio signal to the binding post to
avoid any electric shock!
BRIDGED
BRIDGED
CH1
PARALLEL
STEREO
B IDGED
INPUT
CH3
CH4
PARALLEL
STEREO
BRIDGED
INPUT
CH1/CH2
LF30HZ
FILTER
OFF ON
PUSHPUSH
CH3/CH4
LF30HZ
FILTER
OFF ON
BRIDGED
CH1 CH2
MONO
BRIDGED
CH3 CH4
MONO
PUSHPUSH
CH2
OUTPUT
OUTPUT
CH1
K
O
L
K
O
L
CH2
K
O
L
1+
1
1 1
CH2
2+
BRDGED
1+
CH3
1+
CH4
2+
BRDGED
1+
MODE
2
SERIA
2+
MADE N CH NA
DESIGNED N I ALY
BREAKER
CH4
K
O
L
1
1 1
2
2+
220 240V 50/60Hz
RatedPower
Consumpton 3000W
7
8
9 10111213 14
6
SPOTLIGHT
3. CONTROL ELEMENTS
12 LOW FREQUENCY FILTER
This Filter rolls off audio signals below 30Hz. In this way bass performance will
be improved, because the subsonic motion of the cone will be cut out and more
power is made available to the woofer in the audible range of frequencies. If you
want our view: Keep the Filter ON most of the time unless you are filtering the
signal before the input of the amplifier. Especially vented speakers (bass-reflex)
are very sensitive to subsonic frequencies (below 30Hz).
13 OUTPUT MODE SELECTOR
The D series power amplifier presents three operating modes:
-StereoMode
In this mode, CH A and CH B operate independently (as a normal stereo amplifier)
The CH A input signal will be output from the CH A output connector, and CH B
input signal will be output from the CH B output connector.
- Parallel Mono Mode
In this mode, CH A input signal will be output from the output connectors of both
channels. Detail wiring diagram you can refer to chapter 4.
- Bridged Mode
In this mode, CH A input signal will be output from the bridge-mono output connector.
Detail wiring diagram you can refer to chapter 4.
14 COOLING FAN
This fan secures enough cooling for your amplifier. The airflow is front-to-rear. The fan
speed is electronically regulated depending on the temperature of the power devices.
7
4. OPERATION-In Stereo Mode
The D series power amplifiers provide three operating modes: stereo mode,
parallel (mono) mode and bridged mode, you can decide each specific operating
mode according to your actual application circumstance.
In this mode, channel A and channel B operate independently (as a conventional
stereo amplifier). The channel A input signal will be output from the channel A
output connectors, and the channel B input signal will be output from the
channel B output connectors.
CHANNEL 1
PUSH PUSH
CH1 CH2 CH1/CH2
PARALLEL
STEREO
BRIDGED
BRIDGED
INPUT
CHANNEL 2
For D1/D3(2-CHANNEL)
LF30HZ
OFF ON
FILTER
PARALLEL
STEREO
BRIDGED
CH1 CH2
BRIDGED
MONO
TOREDUCE THE R SKOF FIRE
ORELECTR C SHOCK DONOT
EXPOSETH S APPARATUSTO
RAINOR MOI TURE
SEEINSTRUCTION BEFORE
USING!
OUTPUT
WARNING
K
O
L
CHANNEL 2
CHANNEL 1
CH1
CH2
K
O
L
1+
CH2
2+
BRIDG D
1+
MODEL
1+
SERAL
2+
DESGNED IN TALY
BREAKER
SUPPLYAC
220240V~50Hz
MAX NPUT 2000W
+
+
BRDGED
BRDGED
For D2/D4(4-CHANNEL)
PARALLEL
STEREO
BRIDGED
USHUSH
CH2
CH1
PARALLEL
S EREO
BRIDGED
INPUT
CH3
PARALLEL
STEREO
BRIDGED
INPUT
CH1/CH2
LF30HZ
FLTER
OFF ON
USHUSH
CH3/CH4
CH4
LF30HZ
OFF ON
FLTER
CHANNEL 1
+
BRDGED
CH1 CH2
MONO
BRDGED
CH3 CH4
MONO
+
CHANNEL 3
Use either the binding post
or the speak on
OUTPUT
OUTPUT
CHANNEL 2
+
C
K
O
C
K
O
+
CHANNEL 4
CH1
CH2
K
O
L
1+
1+ 1
CH2
2+
BRDGED
1+
CH3
1+
CH4
2+
BRDGED
1+
MODEL
SERAL
2+
MADEIN CHINA
DESGNED IN TALY
BREAKER
CH4
K
O
L
1
1+ 1
2+
220-240V 50/60Hz
Ra ed Power
Consumption3000W
8
4. OPERATION-in Parallel Mode
In this mode, the channel A input signal will be output from the output connectors
of both channels. The channel B input jack is not used; the channel A and B
volumes can be adjusted independently. Use the Parallel Mode when you want to
drive two speakers with only one input signal keeping separate control of the
volume of the two channels.
NOTE: since you are not using the channel B input you can use this socket
to "daisy-chain" the signal to another amplifier.
CHANNEL 1
NO USING
PUSH PUSH
CH1 CH2 CH1/CH2
BRIDGED
CH1
BRIDGED
CH3
BRIDGED
For D1/D3(2-CHANNEL)
PARALLEL
INPUT
STEREO
BRDGED
LF30HZ
FILTER
OFF ON
For D2/D4(4-CHANNEL)
PARALLEL
STEREO
BRIDGED
USUS
CH1/CH2
CH2
PARALLEL
INPUT
PARALLEL
INPUT
STEREO
STEREO
BRDGED
BRIDGED
CH4
LF30HZ
FLTER
OFF ON
USPUSH
CH3/CH4
LF30HZ
FLTER
OFF ON
K
O
L
OUTPUT
WARNING
TOREDUCE THER SK OF F RE
ORELECTR C SHOCK DONOT
EXPOSETH S PPARATUSTO
RAINOR MO STURE
SEEINSTRUC ION BEFORE
USING!
CHANNEL 2
BRDGED
PARALLEL
STEREO
BRIDGED
BRDGED
CH1 CH2
MONO
CHANNEL 1
CHANNEL 1 CHANNEL 2
+
BRDGED
CH1 CH2
MONO
BRDGED
CH3 CH4
MONO
OUTPUT
OUTPUT
+
K
O
L
K
O
L
K
CH1
CH2
O
L
MODEL
1
1
+
CH2
2
2
SERAL
2+
1
DESGNED IN I A Y
BREAKER
SUPPLYAC
220240V~50Hz
MAX NPUT 2000W
+
+
K
CH1
CH2
O
L
1+
1+
CH2
2+
BRDG D
1+
CH3
1+
CH4
2+
BRDG D
1+
M DEL
SERAL
2+
MADE N CH NA
DESIGNED N TALY
BREAKER
K
CH4
O
L
+ 1
2+
220 240V ~50/60Hz
RatedPower
Consumpion 3000W
+
+
CHANNEL 3 CHANNEL 4
Use either the binding post
or the speak on
9
4. OPERATION-In Bridged Mode
In this mode, the channel A input signal will be output from the bridge output
connectors. (The 2 RED binding post) In this case, use the channel A volume
control to adjust the volume, keep the volume control of channel B turned
completely down (counter clockwise). Bridged mode is intended for driving loads
withatotalimpedanceof8ohmsorgreater.InBridgeModeyouwillcombine
the power of both channels into one speaker. You will have available massive
amount of power so check carefully the power handling of your speaker before
operation.
For D1/D3(2-CHANNEL)
RIDGED
LF30HZ
FILTER
OFF ON
PARALLEL
STEREO
BRIDGED
BRIDGED
CH1 CH2
MONO
TOREDUCE THERISK OF FIRE
ORELECTR C SHOCK DONOT
EXPOSETH S APPARATUSTO
RAINOR MOISTURE
SEEINSTRUCT ON BEFORE
USING!
NO USING
O
L
OUTPUT
WARNING
CHANNEL 2+
CHANNEL 1+
CH1
CH2
L
MODE
+
1+
CH2
+
BRDG D
SERA
2+
+
DESGNED N TALY
BREAKER
SUPPLYAC
22 -240V~50Hz
MAX NPUT 2000W
+
CHANNEL 1
NO USING
PUS PUSH
CH1 CH2 CH1/CH2
BRIDGED
PARALLEL
INPUT
STEREO
For D2/D4(4-CHANNEL)
PARALLEL
STEREO
BRIDGED
PUSHPUSH
CH1
PARALLEL
STEREO
BRIDGED
BRDGED
INPUT
CH3
PARALLEL
STEREO
BRIDGED
BRDGED
INPUT
CH1/CH2
CH2
CH4
LF30HZ
FILTER
OFF ON
PUSUSH
CH3/CH4
LF30HZ
FILTER
OFF ON
CH1 CH2
CH3 CH4
Use either the binding post
or the speak on
BRDGED
MONO
BRDGED
MONO
OUTPUT
OUTPUT
+
K
K
CH1
O
L
K
O
L
CH2
O
L
1
1
1 1
MODE
CH2
2
2
BRDGED
1
CH3
1
CH4
2
BRDGED
1
ERIA
2+
MADE N CHINA
DESGNED N TALY
BREAKER
K
CH4
O
L
1
1 1
2
2+
220-240V ~50 60Hz
Raed Power
Consumpton 3000W
+
10
5. BLOCK DIAGRAM
DIGIMOD
DIGIMOD
11
6. TECHNICAL SPECIFICATIONS
POWER SPECIFICATIONS
driven 230V
1% THD
0 5% THD
Power Continuous @
Both channels
Power EIAJ@
Both channels driven 230V
Bridged Mode
ELECTRICAL SPECIFICATIONS
INPUT SENSITIVITY
INPUT IMPEDANCE
FREQUENCY RESPONSE
INPUT CLIPPING
VOLTAGE GAIN
DISTORTION(SMPTE-1M)
S/N RATIO
GENERAL SPECIFICATIONS
PROTECTIONS
CONTROLS
INDICATORS
CONNECTORS
POWER SUPPLY
DIMENSIONS(WxDxH)
WEIGHT
4 Ohms
8 Ohms
4 Ohms
8 Ohms
8ohms
16ohms
D1
2 CH Amplifier
2 X 390 W
2 X 240 W
2 X 500 W
2 X 270 W
1 X 1000 W
1 X 520 W
D2 D3 D4
4 CH Amplifier
4 X 390 W
4 X 240 W
4 X 500 W
4 X 270 W
2 X 1000 W
2 X 520 W
2 CH Amplifier
2 X 540 W
2 X 340 W
2 X 750 W
2 X 370 W
1 X 1500 W
1 X 740 W
1Vrms
10 kohms unbalanced, 20 kohms balanced
20 Hz-20 kHz+/-0.1dB, -3 dB points: 10 Hz - 60kHz
10 Vrms (+22 dB)
32dB
0.5%
105dB
On/off muting, DC-fault load grounding relay. Internal fault fuses
Front: AC switch, gain knobs
Rear: low pass filter, mode selector
SIGNAL: green LED CLIP: red LED
POWER: blue LED PROTECTION: red LED
INPUT : balanced combo
OUTPUT: "Touch-proof" binding posts and speak-on jacks.
Available for AC230V,AC115V, 50-60Hz
483x285x88.8 mm
5.5 Kg
483x376x88.8 mm
7.9 Kg
483x285x88.8 mm
5.5 Kg
4 CH Amplifier
4 X 540 W
4 X 340 W
4 X 750 W
4 X 370 W
2 X 1500 W
2 X 740 W
483x376x88.8 mm
7.9 Kg
12
6. WARRANTY
1. WARRANTY REGISTRATION CARD
To obtain Warranty Service, the buyer should first fill out and return the enclosed
Warranty Registration Card within 10 days of the Purchase Date.
All the information presented in this Warranty Registration Card gives the
manufacturer a better understanding of the sales status, so as to provide a
more effective and efficient after-sales warranty service. Please fill out all the
information carefully and genuinely, miswriting or absence of this card will void
your warranty service.
2. RETURN NOTICE
2.1 In case of return for any warranty service, please make sure that the
product is well packed in its original shipping carton, and it can protect your
unit from any other extra damage.
2.2 Please provide a copy of your sales receipt or other proof of purchase with
the returned machine, and give detail information about your return address
and contact telephone number.
2.3 A brief description of the defect will be appreciated.
2.4 Please prepay all the costs involved in the return shipping, handling and
insurance.
3. TERMS AND CONDITIONS
3.1 warrants that this product will be free from any defects in materials
LT O
and/or workmanship for a period of 1 year from the purchase date if you
have completed the Warranty Registration Card in time.
3.2 The warranty service is only available to the original consumer, who purchased
this product directly from the retail dealer, and it can not be transferred.
3.3 During the warranty service, may repair or replace this product at its
own option at no charge to you for parts or for labor in accordance with the
right side of this limited warranty.
3.4 This warranty does not apply to the damages to this product that occurred
as the following conditions:
Instead of operating in accordance with the user's manual thoroughly, any abuse
or misuse of this product.
Normal tear and wear.
The product has been altered or modified in any way.
Damage which may have been caused either directly or indirectly by another
product / force / etc.
Abnormal service or repairing by anyone other than the qualified personnel or
technician.
And in such cases, all the expenses will be charged to the buyer.
3.5 In no event shall be liable for any incidental or consequential damages.
Some states do not allow the exclusion or limitation of incidental or
consequential damages, so the above exclusion or limitation may not apply to
you.
3.6 This warranty gives you the specific rights, and these rights are compatible
with the state laws, you may also have other statutory rights that may vary
from state to state.
LT O
LT O
13
NO. 1, Lane 17, Sec. 2, Han Shi West Road, Taichung 40151, Taiwan
SEIKAKU TECHNICAL GROUP LIMITED
http://www.altoproaudio.com Tel: 886-4-22313737
email: alto@altoproaudio.com Fax: 886-4-22346757
All rights reserved to ALTO. All features and content might be changed
without prior notice. Any photocopy, translation, or reproduction of part of this
manual without written permission is forbidden. Copyright 2007 Seikaku Group
c
NF02695-1.3
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