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1. Power switch:  Isolates unit from the line supply. 
2. Power on:        When illuminated indicates AC power is applied to unit. 
3. On:                   Indicates the amplifier is in operation. 
4. Trip:                 Indicates dc. voltage present on amplifier output or amplifier  has   
                            reached an excessive temperature 
5. Bridge: 

       Idicates that bridge mode has been selected 

6. L/R Peak:         Indicates onset of distortion. 
7. L/R Level:        Sets the gain of each channel of the amplifier. 
 
 
PEAK INDICATOR. 
 
When the channel peak indicator lights it is indicating full power of the amplifier and the 
onset of distortion. It not recommended to allow these to light continuously, because 
although it sounds undistorted to the ear, long term damage to the loudspeakers, & horns 
may occur. Reduce your input level, so the lights flash occasionally  

If this is not enough volume, then you are underpowered for your application and should 
consider increasing your power amp size before damage occurs to the rest of your system.  

 
POWERING UP 
 
You can turn the amplifier on or off either at the mains supply socket, or by using the 
green neon rocker switch on the left hand side of the front panel.  
 
Please note: it is good practice to turn down the volume controls during switch on as 
precaution against speaker damage. Which can be caused by instant high level feedback 
from an open channel mixer & mic, or system instability.  
 
On initial switch on, the 'trip indicator' will light; this should  go out after a few seconds 
(when the amplifier supplies have stabilised).  It is not recommended to switch the 
amplifier on and off rapidly several times over a short period. 
 
MONO OR STEREO MODE 
 
Select either mono or stereo mode can be made at any time, using the button at the rear 
of the unit.  In the stereo mode, the left and right channels behave independently.  In the 
mono mode the left and right input signals are summed together and halved and fed to 
both left and right amplifiers. Mono mode is indicated by the depressed button on the rear 
of the unit. 

 
 
 

4. 

BRIDGE MODE 
 
Bridge mode can be selected by using the button at the rear of the unit, the selection will 
be indicated on the front by the yellow lamp.  The 'CH1 & CH3 INPUTS' are the only 
operative inputs, and the 'CH1 & CH3 VOLUMES' are the only operative gain controls for 
each of the bridged pairs.  The total power of either of the amplifier pairs can then be 
developed into an 8 ohm load connected positive to pin 2 on the 'CH1 OUTPUT' XLR and 
negative to pin 2 on the 'CH2 OUTPUT'XLR, or similarly 'CH3 OUTPUT' XLR and 
negative to pin 2 on the 'CH4 OUTPUT'XLR. 

Summary of Contents for QPX1200

Page 1: ...DUAL CHANNEL AUDIO POWER AMPLIFIER OWNERS MANUAL Hz INTERNATIONAL LTD COMBE HOUSE STOKE ST MICHAEL BATH SOMERSET ENGLAND QPX1200 CE 96 ...

Page 2: ...cking 2 Siting the power amplifier 3 Connections 4 Fitting a mains plug OPERATION 1 POWERING UP 2 SELECTING MODE 3 PEAK INDICATOR 5 TRIP INDICATOR AMPLIFIER MAINTENANCE TECHNICAL DATA FAULTS AND THEIR LIKELY CAUSES 1 INSTALLATION ...

Page 3: ...r ventilation and the air is not recycling b Rack mounting Ears are provided for both front and rear support a choice of mounting position is given on the front brackets either proud level with the front panel or sunk by 20mm and flush with the front escutcheon c Care is required when installing these units in a rack It is advised to put the Rack on its back then place all the equipment being fitt...

Page 4: ... CABLES The inputs are electronically balanced for those who require this facility with the tip of the jack being hot and the ring cold or balanced line and the sleeve ground However they can be used unbalanced with standard mono jack plug A link jack input is provided on each input channel so that any of the four channels can be joined together or linked down to another power amplifier in the rac...

Page 5: ... down the volume controls during switch on as precaution against speaker damage Which can be caused by instant high level feedback from an open channel mixer mic or system instability On initial switch on the trip indicator will light this should go out after a few seconds when the amplifier supplies have stabilised It is not recommended to switch the amplifier on and off rapidly several times ove...

Page 6: ...ier enclosed in a sealed rack with no air vents If the trip light fails to extinguish after 30 seconds from cold switch on then there is an internal fault in the amplifier and the relevent speaker s have been disconnected to protect them Advice should be sought from your dealer AMPLIFIER MAINTENANCE The amplifier contains no use serviceable parts inside Maintenance should be mainly preventative ta...

Page 7: ...o reset COOLING 2 fans speed change switched on at 50 deg C INPUTS 1 IEC Mains socket for A C input 8 stereo input link jacks balanced line 2 per ch OUTPUTS 4 XLR male sockets 1 per channel MAINS FUSE 12 5A HRC 20mm POWER FUSES 4 x 10A 20mm internal SIZE 483 X 90 X 290 19 x 3 5 x 11 WEIGHT 17Kg 38lbs MAINS SUPPLY 240 220v or 120 110v A C 50 60 Hz 1 4KVA full power 6 FAULTS AND THEIR LIKELY CAUSES ...

Page 8: ...nsure free air flow into and out of the unit The amplifier will reset itself when cool Or the amplifier has developed an internal fault please consult your dealer As a general rule jack plugs and sockets are very reliable especially if they are regularly connected and disconnected In situations where they are subject to prolonged static use it is good practice to clean the plugs and to clean the s...

Page 9: ...at has been replaced shall become the property of the company and the right is reserved by the company to replace the equipment or repair it at the option of the company 8 This guarantee applies to equipment purchased and used within the E E C The importers of equipment in non E E C countries are responsible for the guarantee of this equipment Parts required under guarantee are free Shipping charg...

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