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General Installation 

DO NOT 

run unbalanced high impedance 

microphone cables near mains, data, 
telephone or 70/100V line cables.

DO NOT 

run 70/100V line cable near data, 

telephone or other low voltage cables.

DO NOT 

exceed 90% of the amplifiers output 

power when using 70/100V line (speech only).

DO NOT 

exceed 70% of the amplifiers output 

power when using 70/100V line (high level 
background music).

DO NOT 

use voice paging horn loudspeakers 

for background music unless the loudspeaker 
has been specifically designed for this 
purpose.

AVOID 

jointing the microphone cable, 

when this is unavoidable make sure a good 
screened connector is used. 

ALWAYS 

use balanced low impedance 

microphone cable terminating to balanced 
inputs on long cable runs.

ALWAYS 

use a mains grade double insulated 

cable for the loudspeaker cable runs when 
run in conduit together with power cables. 

ENSURE 

that all loudspeakers are in-phase.

ENSURE 

that there are no short circuits on 

the loudspeaker line before connecting to the 
amplifier. It is also advisable to check the final 
impedance to the amplifier with a dedicated 
impedance meter to determine power draw is 
within the amplifiers limits.

IMPORTANT

The wires in the mains lead are coloured In 
accordance with the following code:

Green and Yellow:

    Earth (E)

Blue:   

            

Neutral (N)

Brown:     

      

Live  (L)

As the colours of the wires in the mains lead 
of this apparatus may not correspond with the 
coloured markings identifying the terminals in 
your plug proceed as follows:

The wire which is coloured green and yellow 
must be connected to the terminal which is 
marked with the letter N or coloured black.  
The wire which is marked with the letter L or 
coloured red. 

If a 13 Amp (B.S.1363) plug or any other type 
of plug is used, a 5 Amp fuse must be fitted 
either in the plug or at the distribution board.

WARNING  

THIS APPLIANCE MUST BE EARTHED

Summary of Contents for Q-Tech QTA1120P

Page 1: ...Q Tech Commercial Series QTA1120P 1240P Power Amplifiers User Manual PUBLIC ADDRESS AMPLIFIER QTA 1240P OUTPUT LEVEL 8 Pwr 10 8 3 0 3 POWER ...

Page 2: ...run in conduit together with power cables ENSURE that all loudspeakers are in phase ENSURE that there are no short circuits on the loudspeaker line before connecting to the amplifier It is also advisable to check the final impedance to the amplifier with a dedicated impedance meter to determine power draw is within the amplifiers limits IMPORTANT The wires in the mains lead are coloured In accorda...

Page 3: ... Manual Q Tech Commercial Series QTA 1120P 1240P 1 Contents Introduction 2 Description 2 Front Panel Layout 3 Rear Panel Layout 3 Power Source 4 Installation Practice 5 Operation 5 Trouble Shooting 6 Specifications 6 Technical Notes 7 ...

Page 4: ...n to detail your amplifier will deliver its best results Please red the section Constant Voltage Distributed Speaker Systems Demystified Unpacking Please inspect the amplifier carefully immediately after unpacking If you find any damage notify your supplier dealer immediately Only the shipper may file a damage claim with the carrier for damage incurred during shipping Description QTA series of Pow...

Page 5: ... Supply Terminal 12 MIC 4 Aux 1 Selector Switch 6 Speaker Output Terminal 13 Phone Jack Input 7 Phone Jack Output Front Panel Layout PUBLIC ADDRESS AMPLIFIER QTA 1120P OUTPUT LEVEL 8 Pwr 10 8 3 0 3 POWER 1 2 3 VOLTAGE SELECT AC 115 240V 50 60Hz FUSE 250V T5A 24V DC COM 8Ω 70V 100V CAUTION RISK OF ELECTRIC SHOCK DO NOT OPEN CAUTION TO PREVENT ELECTRIC SHOCK DO NOT REMOVE COVER OR BACK NO USER SERVI...

Page 6: ...nto the cables the amplifier to be processed externally and then returned to the power amplifier section of the amplifier The connecting link must be plugged in for normal operation as a mixer amplifier PRE OUT is after the tone controls and the master volume 100V Up to 50m AWG25 26 0 15mm2 50m 200m AWG20 0 5mm2 Over 200m AWG18 0 75mm2 70V Up to 50m AWG24 0 20mm2 50m 200m AWG17 1 0mm2 Over 200m AW...

Page 7: ...nother amplifier When it is connected to another amplifier put the switch on Parallel position to maintain maximum gain Installation Practice Step 1 Take a piece of figure 8 cable connect the stripe coloured wire to the 100V terminal and the uncoloured wire to the COM on the amplifier terminal strip Step 2 Connect the other end of the wire uncoloured to the Com EARTH connection on the ceiling spea...

Page 8: ...ually Blows Fuses Make sure that the speaker line is not shorted Check speaker types ratings and if on correct output Amplifier Keeps on Cutting In Out Make sure that there is adequate ventilation around the amplifier Check the vent slots on the front are not covered or blocked and the fan on the rear is functioning correctly Check also speaker types ratings and for any short circuits on the speak...

Page 9: ... speaker system How to calculate the correct number of speakers and what wattage connection for a given amplifier power If you connect too many speakers to an amplifier you will have distortion overheating of the amplifier and generally poor performance The problem is not really too many speakers it is more a problem of too much wattage draw exceeding the output capability of an amplifier A simila...

Page 10: ...ula See below Determining power by calculating total impedance The alternative to counting the speaker taping watts is to calculate the total impedance of the line which will also indicate the wattage necessary to drive the system correctly The computational formula is voltage squared divided by impedance Power Voltage2 Impedance When the speaker line reaches its top voltage of 70 Volts the formul...

Page 11: ......

Page 12: ...www questaudio net Quest Engineering Pty Ltd 86 Derby St Pascoe Vale VIC 3055 Ph 613 9354 9133 Fax 613 9354 9233 ...

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