QPRO AUDIO QLE 2.4K2 User manual

This manual does not contain all the information about the design, production,
and changes of the equipment, and does not cover all the conditions that may
occur during the installation, use and maintenance.
The information provided in this manual is accurate at the time of delivery of
the equipment, it maybe has been changed because of the product upgrade.
Owner's Manual
Professional Amplifier
POW ER
CLI P
SIG NAL
CLI P
SIG NAL
CLI P
SIG NAL
POW ER
CLI P
SIG NAL
CLI P
SIG NAL
POW ER
CLI P
SIG NAL
POW ER
CLI P
SIG NAL
CLI P
SIG NAL

1、The equipment can only be inserted in the power outlet that is indicated by the manual.Otherwise
it may cause fire or electric shock.
2、Do not place the container with liquid or small metal objects on the equipment. Otherwise, the
liquid or metal falling into the equipment may cause fire or electric shock.
3、Do not place the weight (including the equipment) on the power cord. Otherwise, it may damage
the power cord, which can lead to fire or electric shock.
4、Do not place the power cord in the vicinity of the heater. Otherwise it may lead to melting, causing
a fire.
5、Do not scratch, bend, twist, stretch or heat power cord. Otherwise, it may damage the power cord,
which can lead to fire or electric shock.
6、Pull off the power plug from the power outlet, please grasp the insulation part of the plug, do not
pull the cable. Otherwise, it may damage the power cord and the socket, which can lead to fire or
electric shock.
7、Do not use wet hands to touch the power plug. Otherwise it may cause electric shock.
8、Please do not let water enter the equipment or make it affected with damp. Otherwise it may cause
fire or electric shock.
9、Please do not the use the equipment in the following occasions:
_An unstable platform surface, such as a shaking table or an inclined plane.
_A place where the air is exposed to high humidity or where dust accumulates.
_Exposed to an overheated environment, such as a window in a closed car or in direct sunlight.
_Exposed to splash oil foam, such as steam, stoves, boilers, humidifiers and other places.
10、There are ventilation holes in front and behind the equipment, to avoid the impact of internal
cooling, do not block the ventilation holes.
11、Please keep enough space around the equipment. Reserved space should not be less than: side
5cm, behind 10cm, and air follow unblocked.
12、If you want to move the equipment, please unplug the power plug and unplug all the connecting
cables. Otherwise, it may damage the cable, which can lead to fire or electric shock.
13、Attachment of the equipment (such as machine foot, manual bag, desiccant, etc.) please put them
in the place where children can not get them.
14、Do not open the equipment cover. Otherwise may lead to electric shock. If you think the equipment
needs to be repaired or maintained, please contact the agent.
15、Do not unauthorized change the equipment. Otherwise, it may result in abnormal, fire or electric
shock.
16、If lightning strikes, please close the power switch as soon as possible, and unplug the power cord.
17、The equipment output signal may be high voltage, there is a risk of electric shock, please use a
dedicated connection header.
18、Connect the speakers to the amplifier output socket, can only use special speaker cable.Use of
other cables may cause fire.
19、When connecting to the equipment, please turn off all the audio equipments and speakers.
20、Before turning on the equipment, be sure to turn the volume knob to the minimum. Otherwise, a
sudden burst of sound may damage your hearing.
21、If you will not use the equipment for a long time, please unplug the power cord from the AC power
outlet. Otherwise it could cause a fire.
22、If the power cord is damaged (such as cut off or bare wire), get the replacement from the agent. Or
continue to use the equipment may cause fire or electric shock.
23、If the equipment is shell damage or falling from high, please immediately turn off the power switch,
and unplug the power cord, and contact the agent. Otherwise it may cause fire or electric shock.
24、When any abnormal, such as smoke, odor, etc., please immediately turn off the power switch,
unplug the power cord, and contact the agent. Otherwise, it may lead to fire or electric shock.
01
IMPORTANT SAFETY INSTRUCTIONS

Thank you for your trust, buy our class D power amplifier!
Our company focuses on class D power amplifier. The high level of R&D team, experienced
production team and high-quality technical support team ensure that our products used in a variety
of environment are stable and reliable, and bring you a pleasant experience.
In order to maximize the efficiency of the equipment and bring you a pleasant experience,
please read this manual carefully.
1 Preface
1.1 Performance overview
a、Compatible for EMC and SAFTY;
b、High efficiency，energy-saving and emission-reduction；
c、Adopt international high-end manufacturers, the quality is first-class；
d、Small size, light weight, 1U rack space;
e、High reliability, meeting the requirements for reliability of conference
and engineering products；
f、The low noise of the power amplifier and the mute fan；
1.3 How to use this manual
This manual provides the basic information for the proper installation and use of the
equipment, and does not cover all the conditions that may arise in the actual project. For more
information, please visit our website or contact our technical support, system installation
personnel or agents.
Please take care of the sales order or invoice for your purchase of this equipment. You need
to show the credentials when the product is guaranteed.
1.4 Warning sign
02
PROFESSIONAL POWER AMPLIFIER
Important operation or special note
Risk of electrical shock
1.5 Maintenance information card
This manual attached with "maintenance information card", if the equipment sends back to the
agent or service center to repair, please fill in the form and transported together with the equipment.
1.2 Functions
a、Stereo/mono/bridge selectable；
b、1V and 0.7V，2 grades gain selectable；
c、 Balance XLR input，Speakon output;
d、Clipper limiter: prevent the output square wave damage the speaker；
e、Amplifier output DC protection；
f、 Output overload/short-circuit protection；
g、High temperature power compression,over-temperature protection；
h、 Undervoltage protection for power supply.

* Saving energy, reducing operating costs
* Environmental protection
Aluminum, copper and steel are greatly reduced, saving energy and resources;
reduce transportation emissions 70%.
Climate warming is a challenge to the world, energy saving and emission reduction
are effective measures to solve the climate.
We are committed to providing environmental friendly products. For blue sky ,
white clouds, green mountains and rivers ,let us act together!
3 Installation
3.1 check out of the box
Open packaging and check whether the equipment is damaged in the transportation .
If the equipment is damaged, please inform the shipping company immediately, only you
have the right to request compensation for shipping damage. Please save the packing case
as evidence of damage for the shipping inspection. We will provide the necessary assistance
for you.
It is recommended that you save all packaging materials for use in the transportation
equipment. Do not transport the equipment in the absence of an outer package, so as not
to damage the equipment.
Packing list:
amplifier one pcs User's manual one pcs
Power cord one pcs Speakon connection head one pcs
Machine foot four pcs
03
3.2 Outline dimensions
352mm
(291mm)
483mm
44mm
2 Environmental protection, energy saving, cost saving
* Low working temperature, reliability will be improved obviously.
* The size and weight are only 1/3 of tradition amplifier.
* The cost for transportation, handling, installation will reduce obviously.
POWER
CLIP
SIGNA L
CLIP
SIGNA L
1+=CH -B POS
1-=CH -B NEG 1+=CH -A POS; 1 -=CH- A NEG
2+=CH -B POS; 2 -=CH- B NEG
BRID GE:1+=POS;2-=N EG
CH- A/B
CH- B
1+=CH -D POS
1-=CH -D NEG 1+=CH-C P OS; 1-= CH-C NE G
2+=CH -D POS; 2 -=CH- D NEG
BRID GE:1+=POS;2-=N EG
CH- C/D
CH- D
MONO
BRDG
1V
MONO
BRDG
1V
A PRODUCT OF
QPRO TECHNOLOGY
GERMANY

3.3 Installation preparation
Warning: before installation, please confirm that you see and read the
safety warning.
Before installation, make sure that the power cord is not connected to the
power outlet; The power switch is turned off; The volume knob is completely
closed (counter clockwise to the limit).
The equipment is high power, around a strong magnetic field. Keep the
signal sensitive equipment away (preferably not less than 20cm),
ortherwise may produce noise.
For the normal operation, following parts is needed:
1、Input connection cable
2、Output connection cable
3、Ethernet cable (for Ethernet interface power amplifier)
4、Cabinets or equipment mounting rack
04
3.4 Cooling instructions
The cooling mode of the equipment is as follow:
the cold air is sucked through the ventilation hole of
the front panel, and the heat are taken out from the
rear panel. In order to ensure good heat dissipation,
please put the equipment in the 0℃~40℃ environment,
and ensure that the front and rear panel airway open.
If the temperature exceeds 85 degrees, output voltage
will be reduced, avoid excessive temperature rise. If
the temperature continues rise up to 90 degrees, the
power amplifier will be shunted down, when the
temperature dropped to a safe temperature, the
equipment will restart automatically.
After working for some time, if the cooling effect
is not good, please turn off the equipment and remove
the dust net cover to clean up the dust.
3.5 Power cord
The grounding end of the power cord must be grounded,
otherwise there is a risk of electric shock!
PROFESSIONAL POWER AMPLIFIER
The power cord must have sufficient current capacity, AC power supply voltage and frequency
must be in range of ±10% of the nominal value.

05
3.6 Input / output line
Common knowledge:
Try to use the shielded wire, the higher density shielding layer is the better.
Try to select balance connection for input, to reduce noise interference.
Selection of non balance connection, the shorter the better, preferably not more than 3m.
The weak signal line should avoid to parallel with the power line and the power output line,
otherwise it might produce noise.
Before changing any connection, please turn off all equipments. Otherwise, it may cause
damage to hearing and speakers.
Balanced analog input and
AES3 digital input connection
Non balanced analog input
connection
GND SHIELD
3.61 Stereo Mode/Mono mode
3.62 Bridge mode

06
PROFESSIONAL POWER AMPLIFIER
4 Operating instructions
Before installation, make sure that the power cord is not connected to
the power outlet; the power switch is turned off; the volume knob is
completely closed (counter clockwise to the limit).
4.1 Protection speaker
Clipping not only makess sound distortion, but also damages the tweeter, you can reduce the
input signal to avoid clipping.
Strong sub signal will cause the speaker burned. The high level low frequency signal caused
by the falling of the microphone is a typical sub acoustic signal. One of the following ways to
prevent sub sonic signals should be used:
a、Installing a high pass filter between the mixer and amplifier.
b、Turn on the high pass filter in the mixer. Without affecting the use, the filter frequency is
set as high as possible. For example, for the music signal is set to 35Hz, for the microphone set to
75Hz.
4.2 Attention
In order to achieve the best performance and the highest security, please pay attention:
1、Before use, you need to configure the amplifier, including the input and output lines.
Improper wiring will lead to the equipment can not work properly. For information about connection
and configuration, please refer to the “installation” section of this manual.
2、Be careful when connecting, selecting the input signal and controlling the output level.
This can avoid unnecessary trouble.
3、 Do not connect the ground wire of the input and output cable together . This will form a
ground loop and cause oscillations.
4、Do not connect the output cable to the power supply, Otherwise it may cause electric shock.
5、Without authorization, modify the circuit will be dangerous, and the agents will not provide
any services.
6、Do not use the amplifier in the SIG LED continuous flashing yellow.
7、Do not make mixer overload, otherwise it will send clipping signals to the amplifier. Power
amplifier will accurately reproduce such signals, the speaker may be damaged.
8、Do not use the amplifier under the condition of lower than the nominal load. Too low load
may cause amplifier output protection and premature clipping ,damage the speaker.
9、When the amplifier is turned on, the output port may be fatal.
Important note: our company is not responsible for the damage caused by
excessive use.

07
Power switch ON/OFF control. It is ON ,as “I” is pressed down.
Volume
POWER As the power supply is working, LED is green.
Adjust the output amplitude of the amplifier.
CL IP
As the output signal is distorted by more than 1%, LED is yellow.
FAULT
As there is protection,LED is red.
Female XLS :Balanced audio input plug
Power supply input
Signal input
Male XLS :Balanced audio input plug.
Signal input
Sensitivity Switch
Power Connector:20A Neutrik® powerCON.
Power Cord:3×1.5mm².
Set to 1V, the amplifier Sensitivity is 1V;
illustration
function
Icon
illustration
function
Icon
4.3 Operation panel
SIGNAL
As the input signal is greater than "-32dB", LED is green.
Speakon
Four core SPEAKON speaker socket: When the amplifier is in the Stereo
mode, CHA\CHB will connect through this socket, the method is below: 1+,
1-.
Mode Switch
STEREO Mode
Channel A and Channel B work independently. The input signal of the CHA
outputs from the CHA output socket and the same as CHB.
MONO Mode
Channel A and channel B work independently. The output of the channel A is
from the input signal A; the input of the channel B is from the input signal A.
BRIDGE Mode
Channel A and channel B work at the same time, and the output is from input
signal A.
CLIP
SIGN AL
POWE R
CLIP
SIGN AL
POWE R
CLIP
SIGN AL
CLIP
SIGN AL
1+=C H-B POS
1-=C H-B NEG 1+=C H-A POS ; 1-=CH -A NEG
2+=C H-B POS ; 2-=CH -B NEG
BRI DGE:1+=POS ;2-=NEG
CH- A/B
CH- B
1+=C H-D POS
1-=C H-D NEG 1+=CH- C POS; 1- =CH-C N EG
2+=C H-D POS ; 2-=CH -D NEG
BRI DGE:1+=P OS;2-=NE G
CH- C/D
CH- D
MONO
BRDG
1V
MONO
BRDG
1V
A PRODUCT OF
QPRO TECHNOLOGY
GERMANY
1+=C H-B POS
1-=C H-B NEG 1+=C H-A POS ; 1-=CH -A NEG
2+=C H-B POS ; 2-=CH -B NEG
BRI DGE:1+=P OS;2-=NE G
CH- A/B
CH- B
MONO
BRDG
1V
A PRODUCT OF
QPRO TECHNOLOGY
GERMANY

08
PROFESSIONAL POWER AMPLIFIER
Rated Output
Power(THD+N=
1%,1kHz
continue sine
wave, all
channel driving)
8Ω/Stereo
4Ω/Stereo
16Ω/Bridge
8Ω/Bridge
Output RMS voltage
THD+N
5 Specification
Cross-talk
Frequency response
Input impedance
Damp factor
SNR
Main power
Protection
Size(W×H×D)
Net weight
20kΩ（Balance），10kΩ（Unbalance）
Under voltage, DC, Over temperature, Over load limiter, Short protection.
6 Maintenance
The internal circuit of the equipment is very complicated and can only be maintained by the
trained professional technicians. If a failure occurs, contact our technical support.
When the equipment is sent back to the maintenance, please fill in the "maintenance
information card" and send it back with the equipment together.
Do not transport any attachments with the equipment, such as power lines, manuals, etc..
These articles are not required for maintenance, and we are not responsible for these items.
Adequate protection must be given to the equipment. We recommend the use of the original
packaging materials.
7 Packing directions
1、Please fill out the attached "Maintenance Information Card" in the back of the manual.
2、Do not transport the unit with any accessories, such as the wires, hardware and the manual.
The product's repair does not need these items, and these items we are not responsible for.
3、When transporting the products, it must be fully protected. We recommend that you send
back to repair with the original packaging.
4、If you transport the unit with your own packaging, the simple packaging at least meets the
following requirements:
a、Use the double-layer carton which has passed the 275 PSI (PSI: pressure units, 1kg/cm²
approximately 14.5 PSI) burst test, and leave 8cm space to fill the solid foam polystyrene at the six
surfaces.
b、Use enough sealing tape to seal the carton.
c、Do not use thin carton. The damage due to the poor packaging will not be able to enjoy
the warranty.
Sensitivity
1Vrms,0.7Vrms(Rated Power,1kHz)
≥75dB(20Hz-1kHz,below Rated Power)
±0.2dB(10% Rated Power,20Hz-20kHz,8Ω)
2X450W
2X600W
1X900W
1X1200W
60.0V
0.05%(10% Rated Power, typical)
2X800W
2X1200W
1X1600W
1X2400W
80.0V
4X600W
4X900W
2X1200W
2X1800W
69.3V
≥1000(8Ω,20Hz-200Hz)
≥100dB(A weighted 20Hz-20kHz)
QLE 2.4K2 QLE 1.2K2QLE 3.6K4
Model
480x45x352mm
220VA C(±10%)，50/60Hz
5.9kg 6.8kg 5.9kg

09
8 Maintenance outside the warranty
First we will detect the equipment, and tell you the maintenance fee, you need to pay, then
we begin to repair. If you do not agree with the maintenance, please contact the company
customer service center to reclaim equipment as soon as possible. The company has no obligation
to keep your equipment, if 30 days yet not to get back to your equipment, the company will have the
right to dispose of.
9 Warranty
We provide three (3) years warranty from the buying date, for any reason caused failure
(except Items not included in the scope of the warranty).
10 Items not included in the warranty
Warranty applies only to new products within the warranty period. This warranty does not
cover following cases: damages due to improper use, accident; losses be insured by the insurance
contract; serial number to be defaced, modified or erased; damages caused by improper transport
packaging; unauthorized maintenance or modification of the product.
11 Warranty responsibility
For any defect, regardless of fault reason (except items not included in the scope of the
warranty) we will remedy by repairing, replacing, or refund (we can not provide replacement
services, and repair can not solve the problem or can not provide timely repair, otherwise we will
not choose a refund). If you choose a refund, you must return the faulty products to us free of
charge, and do not retain any lien or mortgage. Refunds shall be the same as the actual purchase
price, excluding interest, insurance, handling and other expenses. Warranty can only be
performed in authorized service center or factory. We will repair the product defects and deliver
the product in a reasonable time.
12 How to obtain warranty service
You must inform us your warranty service in the warranty period. Our authorized service
center takes the corresponding quality assurance measures within the reasonable time after
receiving the defective products. If you are not satisfied with the result of the repair, please inform
us immediately.
13 Indirect or accidental damage Disclaimer
You have no right to receive any compensation for any damage caused by any defects in our
new products, include any damage caused by this type of defect to other products。
The company is not responsible for any loss incurred directly or indirectly as a result of
equipment damage。
14 Warranty modification
No one has the right to expand, or modify this warranty. This warranty will not be prolonged
because you did not use the equipment.
15 Design change
We reserve the right to change the design of any product at any time without notice, and do
not undertake the obligation to make corresponding changes to the products previously produced.

16 Buyers legal remedy
After the expiration of the warranty, the company will have the right to stop the implementation
of any quality assurance measures.
This statement will take precedence over any other statements contained in this manual.
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