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QTA-

1120P/1240P

 

User Manual

User Manual

Q-Tech Commercial Series

QTA-1120P/1240P

6

Trouble Shooting

If the amplifier fails to work as required, 
please check the following:

No Power, No Lights

Make sure amplifier power switch is on. 

• 

Make sure mains power switch is on at 

• 

the wall. 
Check the mains and DC fuse. 

• 

Replace with only the correct type and 

• 

rating.

Distorted Output

Check that the speaker type is correct for 

• 

the output that you are using (ie. 4-16

, or 

100V line).
Check for any short circuits on the speaker 

• 

line.

Very Low Output Volume

Make sure that the speaker line is not 

• 

shorted. 
Check speaker types and ratings.

• 

Check that the parallel/mono switch is 

• 

correctly set.

Continually 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 speaker line.

Specifications

Type

Booster Amplifier

Model

QTA-1120P QTA-1240P

Output Power (RMS):

120W

240W

Power 

Supply

Mains 
Voltage

AC 115V or 230V 

50/60Hz 

Battery 
Voltage

DC 24V

Total Harmonic Distortion

<= 1% @ 1KHz, 
rated power

Sensitivity

1V, 100mV @ 10K ohm

Outputs

8

, 70V, 100V

Signal to Noise Ratio4

86 dB

Indicator

Power On, Level

AC Power Consumption

320W

640W

DC Power Consumption

8A

15A

Dimensions (mm)

88(H) x 425(W) x 305(D)

Weight

8.2 Kgs

10.6Kgs

Mounting options

Desktop or 19” rack

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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