Toa DA-1250D-AS User manual

OPERATING INSTRUCTIONS
DUAL POWER AMPLIFIER DA-1250D
1. IMPORTANT SAFETY INSTRUCTIONS ........................................................................................ 2
2.
SAFETY PRECAUTIONS ................................................................................................................ 2
3. GENERAL DESCRIPTION. .............................................................................................................
5
4. NOMENCLATURE AND FUNCTIONS ............................................................................................ 5
5. CONNECTIONS .............................................................................................................................. 7
6.
SYSTEM CONNECTION CASES .................................................................................................... 8
7.
THERMAL DISSIPATION ............................................................................................................... 9
8. POWER LEVEL ADJUSTMENT ......................................................................................................10
9. TROUBLESHOOTING ....................................................................................................................11
10. SPECIFICATIONS ...........................................................................................................................12
11. DIMENSIONAL DIAGRAM ...............................................................................................................12
TABLE OF CONTENTS
Thank you for purchasing TOA's Dual Power Amplifier.
Please carefully follow the instructions in this manual to ensure long, trouble-free use of your equipment.

1. IMPORTANT SAFETY INSTRUCTIONS
Read these instructions.
Keep these instructions.
Heed all warnings.
Follow all instructions.
Do not use this apparatus near water.
Clean only with dry cloth.
Do not block any ventilation openings. Install in accordance with the manufacturer's
instructions.
Do not install near any heat sources such as radiators, heat registers, stoves, or other
apparatus(includingamplifiers) that produce heat.
Do not defeat the safety purpose of the polarized or grounding-type plug. A grounding
type plug has two blades and a third grounding prong. If the provided plug does not fit into
your outlet, consult an electrician for replacement of the obsolete outlet.
Protect the power cord from being walked on or pinched particularly at plugs, convenience
receptacles, and the point where they exit from the apparatus.
Only use attachments/accessories specified by the manufacturer.
Use only with the cart, stand, tripod, bracket, or table specified by the manufacturer, or
sold with the apparatus. When a cart is used, use caution when
moving the cart/apparatus combination to avoid injury from tip-over.
Unplug this apparatus during lightning storms or when unused
for long periods of time.
Refer all servicing to qualified service personnel. Servicing is
damaged in
any way, such as power-supply cord or plug is damaged, liquid has been spilled or objects
have fallen into the apparatus, the apparatus has been exposed to rain or moisture, does
not operate normally, or has been dropped.
Servicing is required when the apparatus has been
2. SAFETY PRECAUTIONS
Before installation or use, be sure to carefully read all the instructions in this section for
correct and safeoperation.
Be sure to follow all the precautionary instructions in this section, which contain important
warnings and/orcautions regarding safety.
After reading, keep this manual handy for future reference.
Safety Symbol and Message Conventions
Safety symbols and messages described below are used in this manual to prevent bodily injury
and property damage which could result from mishandling. Before operating your product,
read this manual first and understand the safety symbols and messages so you are thoroughly
The exclamation point within an equilateral triangle is intended to alert the user to
the presence of important operation and maintenance (servicing) instruction in
the literature accompanying the appliance.
aware of the potential safety hazards.
Indicates a potentially hazardous situation which, if
mishandled, could result in death or serious personal
WARNING injury.
2

When Installing the Unit
Do not expose the unit to rain or an environment where it may be splashed by water or other
liquids, as doing so may result in fire or electric shock.
Use the unit only with the voltage specified on the unit. Using a voltage higher than that which
is specified may result in fire or electric shock.
Do not cut, kink, otherwise damage nor modify the power supply cord. In addition, avoid using
the power cord in close proximity to heaters, and never place heavy objects -- including the unit
itself -- on the power cord, as doing so may result in fire or electric shock.
Avoid installing or mounting the unit in unstable locations, such as on a rickety table or a
slanted surface. Doing so may result in the unit falling down and causing personal injury and/or
External wiring connected to the terminals marked with requires installation by an instructed
The apparatus shall be connected to a mains socket outlet with a protective earthing connection.
The socket-outlet shall be installed near the equipment and the plug (disconnecting device) shall
be easilyaccessible.
When the Unit is in Use
Should the following irregularity be found during use, immediately switch off the power, disconnect
the powersupply plug from the AC outlet and contact your nearest TOA dealer. Make no further
attempt to operate the unit in this condition as this may cause fire or electric shock.
·If you detect smoke or a strange smell coming from the unit
·If water or any metallic object gets into the unit
·If the unit falls, or the unit case breaks
·If the power supply cord is damaged (exposure of the core, disconnection, etc.)
·If it is malfunctioning (no tone sounds.)
components inside the unit. Refer all servicing to your nearest TOA dealer.
property damage.
person.
To prevent a fire or electric shock, never open or remove the unit case as there are high voltage
Do not place cups, bowls, or other containers of liquid or metallic objects on top of the
unit. If they accidentally spill into the unit, this may cause a fire or electric shock.
Do not insert nor drop metallic objects or flammable materials in the ventilation slots of the
unit's cover, as this may result in fire or electric shock.
When Installing the Unit
Never plug in or remove the power supply plug with wet hands, as doing so may cause electric
shock.
When unplugging the power supply cord, be sure to grasp the power supply plug; never pull
on the cord itself. Operating the unit with a damaged power supply cord may cause a fire or
When moving the unit, be sure to remove its power supply cord from the wall outlet. Moving the unit
with the power cord connected to the outlet may cause damage to the power cord, resulting in fire
or electric shock.When removing the power cord, be sure to hold its plug to pull.
Indicates a potentially hazardous situation which, if mishandled,
could result in moderate or minor personal injury, and/or property
CAUTION damage.
electric shock.
3

Do not block the ventilation slots in the unit's cover. Doing so may cause heat to build up
inside the unit and result in fire.
Avoid installing the unit in humid or dusty locations, in locations exposed to the direct sunlight,
near the heaters, or in locations generating sooty smoke or steam as doing otherwise may
result in fire or electric shock.
To avoid electric shocks, be sure to unplug the unit's power supply cord when connecting
speakers.
Be sure to follow the instructions below when rack-mounting the unit. Failure to do so may
cause a fire or personal injury.
·Install the equipment rack on a stable, hard floor. Fix it with anchor bolts or take other
arrangements to prevent it from falling down.
·When connecting the unit's power cord to an AC outlet, use the AC outlet with current
capacity allowable to the unit.
·No rack-mounting screws are supplied with the unit. Separately prepare the appropriate
screws for the rack.
When the Unit is in Use
Do not place heavy objects on the unit as this may cause it to fall or break which may
result in personal injury and/or property damage. In addition, the object itself may fall off and
cause injury and/or damage.
Make sure that the volume control is set to minimum position before power is switched on.
Loud noise produced at high volume when power is switched on can impair hearing.
Do not operate the unit for an extended period of time with the sound distorting. This is an
indication of a malfunction, which in turn can cause heat to generate and result in a fire.
If dust accumulates on the power supply plug or in the wall AC outlet, a fire may result. Clean
it periodically.In addition, insert the plug in the wall outlet securely.
Switch off the power, and unplug the power supply plug from the AC outlet for safety
purposes when cleaning or leaving the unit unused for 10 days or more. Doing otherwise may
cause a fire or electric shock.
Clean the unit regularly
Contact your TOAdealer as to the cleaning. If dust is allowed to accumulate in the unit
over a long period of time, a fire or damage to the unit may result.
Clean the power supply plug
If dust accumulates on the power supply plug or in the wall AC outlet, a fire may result.
Clean it periodically. In addition, insert the plug in the wall outlet securely.
During maintenance or leaving the unit unused
Turn off this unit's power switch, and unplug the power supply plug from the AC outlet for
safety purposes when cleaning or leaving the unit unused for 10 days or more. Doing
otherwise may cause a fire or electric shock.
The lighting flash with arrowhead symbol, within an equilateral triangle, is intended
to alert the user to the presence of uninsulated "dangerous voltage" within the
product's enclosure that may be of sufficient magnitude to constitute a risk of
electric shock to persons.
4

3. GENERAL DESCRIPTION
The DA-1250D is 2-Channel Digital Power Amplifier featuring ligtweight, compact and high power output.
It delivers 1250W x 2 channels (4output).
It can be mounted an EIA standard equipment rack (2 unit size).
4. NOMENCLATURE AND FUNCTIONS
[Front]
1. Suction hole
2. Input volume control
Turn the knob clockwise to increase the volume and counterclockwise to decrease it.
Stereo/Paralle Mode : volumes of CH1 and CH2 control independently .
Bridge Mode : CH1 knob controls both volumes, CH2 knob lose efficacy.
3. LED indicator
PROTECT : Lights red when either protection circuit action.
CLIP : Lights red when compressor/limiter is protecting the amplifier from input overload.
-5dB : Lights green when output signal around -5dB than full power.
-10dB : Lights green when output signal around -10dB than full power.
-20dB : Lights green when output signal around -20dB than full power.
SIGNAL : Lights green when audio signals are output from the speaker output terminal.
POWER : Lights green when the Power switch (4) is switched on.
4. Power switch
Power is switched on and off with each depression of this switch.
5. Mounting hole
Can be mounted an EIA standard equipment rack (2 unit size).
5
①
③
②④
⑤

[ Rear]
6. Socket with fuse
Connects to power source with AC power supply cord.
The Standard Voltage : AC 100 ~ 240V.
Dissipation Power : 1100W. .
Fuse ratings : T12AL 250V.
7. Fan
8. Speaker output terminal
Speaker output, Speakon ( NL4 ) terminal.
Connects to speakers. Refer to p.7 and p.8.
9. Signal input
20kΩ(balanced) / 10kΩ(unbalanced), XLR-F connector.
Connects to Signal source.
6
  
10. Sensitivity selector switch
Selects the input
Refer to p.8. .
11.
Mode selector switch
Refer to p.8.
Selects the mode of input as follows: Bridge / Parallel / Stereo.
12. Signal output (LINK)
XLR-M connector.
Connects to another one input terminal of the power amplifier.
Refer to p.7.


5. CONNECTIONS
[ Cable end treatment]
NOTES: The quality of your soldering is very important virtual welding or soldering errors, Would be
likely to affect the normal use or even failure.
NOTES: T
It can work good from 8ΩΩ
he speaker connector can work from 4-16Ωin srereo or parallel model.
[ Inputs]
[ Outputs]
BLACK
RED
20mm
8mm 0.8”
0.3”
7
Speakon ( NL4 )
CH1
CH2
Negative/black/nero
Positive/red/rosso
Positive/red/rosso
Negative/black/nero
Signal output LINK
Signal input
Sensitivity selector switch
Mode
selector switch
INPUT
Balanced male XLR
1
2
3

6. SYSTEM CONNECTION CASES
8
Speaker Signal source
Connection cases
Bridge mode
BLACK
RED
Parallel mode
Stereo mode
OR
n.c.
n.c.
n.c.
n.c.
BLACK
RED
BLACK
RED
BLACK
RED
RED
BLACK
RED
BLACK

7. THERMAL DISSIPATION
Stack installation
To ensure the cooling environment, please meet the following condition.
> 20CM
HOT AIR
COOL AIR COOL AIR
In order to have a good heat
dissipation condition for amplifier
please clean the filter after you
finish your install, because the
dust in filter will stop the air vent,
it's not good for the heat
dissipation. And you should clean
the filter net every month.
NOTES:
The ambient temperature should
be lower than 35 ℃ while running
the amplifier.
The first time cleaning of strainer mesh should be right after
installation. Recommend to clean the strainer mesh quarerly.
Pease do not run the product without the dust filter, or it makes
the service life of the product shorten.
Such condition will be considered as no warranty.
To avoid heat protection
To prevent the hot air back to frong airvent.
Install exhaust blower
take the hot air away.
HOT AIR
COOL AIR COOL AIR
NOTES: Keep hot air will not flow
back to the front air vent.
Try your best to keep the
temperature under 35 ℃ even in
extreme condition.
NOTES:
If use in Non-horizontal stack, we
suggest the rear exhaust outlet
up or straight to the vents of the
room.
NOTES:
NOTES:
9

8. POWER LEVEL ADJUSTMENT
Procedure
P ower on
40
18
15
12
9
6
3
0
CLIP
8
+12dB
0
-
40
20
12
6
3
0
3
6
12
CLIP
LINE
GAIN
-10
-3dB + 40
This is a normal step to
adjustment, for more
professional adjustment you
should have a professional
person to do that.
For high power system, the
Power-on order is very
important,not in the order is
likely to damage the
equipment.Therefor we
suggest that you use the
sequence power device.
Music Audition
Adjust the volume from very small to loud slowly, after you confirm
the sound is normal then make it more louder. When the speaker
output is close to its limit, the CLIP light will lights up and you
should turn down your volume now, don't let the CLIP lights on long
time, it means over load, may damage the system.
This step should operated by
professional person, if you
don't know how to do, please
be careful!
Mixer Processor
Input the
stable pink
noise
Put the line
output to 0dB
LEVEL
40
20
12
6
3
0
3
6
12
CLIP
CH
0
12
MAIN
0
12
GAIN
GAIN
LINE
-10 +40
Adjust the
input level of
processor lik
the above
picture
40
18
15
12
9
6
3
0
CLIP
INPUT
LEVEL
Power Level Adjustment
Power amplifier should be in the condition of no load in the following
adjustment process:
Process:
Sound consoleSource Peripheral devices Power Amplifier
Power off
Adjust input
gain
Put the main
output to 0dB
Processor Amp
Mixer
The main output
amplitude set
should be
displayed
as: 0dB
Adjust the output level of
processor, the range like
the above picture shows.
Adjust the volune knob
and make the output level
within the range as above
picture shows.
Then adjust the input
gain to make the main
output less 3dB.
This setting is to ensure
twice power.
NOTES:
NOTES:
NOTES:
LEVEL LEVELGAIN
OUTPUT
LEVEL
10

9. TROUBLESHOOTING
After powered without any response
Measure the outlet with a multimeter to check if
there is power available and when no multimeter,
you can have a test pencil. If the power supply is
normal and the amplifier still no response when
powered then there is something wrong with the
amplifier,need prfessional person to check it.
No signal output
1. Frist check if the signal input is right.
Check the connect of XLR, if the 2 and 3
reverted or the ground is reliable. Different
circuitry design will have different connect way
of the XLR, please follow the 2+、3- to soldering.
It can not be judged by comparing with other
amplifiers (including other amplifiers in the
same factory).
2. The signal light don't lights up
If all the signal input is fine and the signal light
don't lights up then may the amplifier has failure,
you need to ask the professional person to
check it.
3. Signal input normal but no sound
The signal light will flash with the change of input
volume, but no sound out, then you can check
the connect of speakon if it is connect good and
the wires are connect right (some times the
problem of the wires connect, check its±1 and ±2
connect), after the check above if still no sound
out, please change a speaker cable and check
again. Because some times also caused by the
bad quality of the Speakon connector problem of
the amplifier
Through experiences, it may caused by the
bad connection of some plugs and the socket.
Output sound distortion
1. After check the signal and loudspeaker
they are fine and still can hear distortion when
small sound, then may the amplifier has
failure, need professional person to check it.
2. Some frequency band has distortion
First, check if the loudspeaker already
overload, normally judge it in 95~105dB for
higher SPL we don't comment here. Here we
just think about the failure recovery of the
amplifier. If in the middle have some rupture
sound and more smaller volume more
obvious, then it should be crossover distortion
of the amplifier and this kind of distortion is
easy to confuse with the failure of loudspeaker
itself. If the amplifier have for problem then you
should send back to the manufactur for repair.
3. Distortion is High SPL
If the sound is normal when small volume and
then you need to check the limit SPL of the
loudspeaker. You can listn it in suitable volume
and if clip light works, then you need reduce
the output. Both loudspeaker and amplifier
have limit, you should use them in their limit if
The protection light blinks
When the PROTECT light works, the amplifier
into the protection mode.
1. Maybe the temperature is too high or output
short or near short and they are not failure they
can recovery after you can use it normally. But
over heat will take more time to recovery. Also
when over heat happened you should cheak
the fan and the temperature of the install
environment, if does you should solve the
problem then can use amplifier. If you think the
speaker was short, you can with a multimeter
to check if the resist is lower than 2 ohm or 1
ohm with DC (Please calibrate the multimeter
to measure for accuracy because of the small
esistance).
2. If the PROTECT awlays light up then it should
be the problem of amplifier, you should send
it back to professional person for repair.
Hum in the system
1. Hum exists even when there is no signal
Please keep the amplifier away from earth
wire of power supply cables, just connect the
fire wire and zero wire, no ground wire. If the
hum is still existing, it can be judged that there
are some problems in the amplifier. Please
get in touch with professionals.
2. Hum exists when the system is completely
connected This is caused by the different
ground voltages in difference devices in the
system, mainly happens when the power
supply is under three-phase distribution
condition, each device is connected to
different phase. This is not caused by amplifier.
The amplifier is required maintenance in the
condition below:
1. If the amplifier smokes or smells burning.
2. If the cabinet has severe indentation and
deformation.
3. If the amplifier are dipped into the water.
4. If the internal components loosen.
5. If AC breaker skips out when current increases.
in very high SPL they have distortion you should
take care of them and reduce the output to the
right position.
Solution experiences, just for reference
A. Combing the electricity the power distribution
,
box using the same one for all if possible.
B. Make sure the grounding wire potential is zero
and force the different grounding wire to the
same level, if the grounding wire itself charged,
indicates that the wire may be connected with
the zero line. Please solve this problem.
c. If unavailable above, then only to disconnect
the ground wires of all devices, which helps to
reduce the AC. But this is not meet the safe
use of electricity, user s must know what will
happen if to do in this way. We do not
recommend the floating use.
11

0 dB = 1 V
The power is tested under the condition of 40ms burst 1kHz sin wave and 1% THD.
* The power is tested under the condition of 20ms burst 1kHz sin wave and 1% THD.
2/3 rated, 8Ω/CH
Note: The design and specifications are subject to change without notice for improvement.
10. SPECIFICATIONS
11.
DIMENSIONAL DIAGRAM
Power Source 100 - 240V AC, 50/60 Hz
Amplification System Class D
Power Consumption
Input CH1-2 : 20kΩ( balanced ) / 10kΩ,
XLR-F connector
Output LINK CH1-2 : XLR-M connector
SPEAKER 1-2 :
2 channels : 700Wx2 (8Ω,1250Wx2 (4Ω)*
1 channels(BRIDGE) : 2500Wx1 (8Ω)*
NL4 SPEAKON connector
Frequency Response 20Hz - 20kHz (+/-3dB)
Total Harmonic Distortion ≤0.15%
S/N Rate ≥100dB
LED Indicator Protect (red)/ Clip (red)/ -5dB(green)/-10dB(green) / -20dB(green) /
Signal(green) / Power(green)
Cooling Air flow from front to rear
Operating Temperature 0℃~+35℃ (32℉ to 95℉)
Operating Humidity 80% RH or less (no condensation)
Finish Case : plated steel sheet, black
Dimensions 483 (W) x 89 (H) x 305 (D) mm [19.02” x 3.5” x12.01”]
Weight 6.1kg [13.45 lb]
Accessory Power Cable ...1
Unit: mm [in]
Side View
430 [ 16.93” ]
89 [ 3.5” ]
Rear View
Front View
483 [ 19.02” ]
305 [ 12.01” ]
267 [ 10.51” ]