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QTA 

2120P/2240P

User Manual

User Manual

Q-Tech Commercial Series

QTA 2120P/2240P

5

Common problems with ceiling 

speaker installations

System is distorting. Check for the following 
causes:

1. Too many speakers set to too high a power 

tapping for the power of the amplifier 

Solution:

 Calculate the total power 

draw and re connect the speakers to a 
lower the wattage tapping. (See below)

  Some cheap ceiling speakers have 

incorrect taping labels. A 10 watt speaker 
may really be drawing 15 or 20 watts. 
The only way to test this is with an 
impedance meter on a single speaker. A 
15% discrepancy can mean that a 100 
watt system will only be able to power 7 
or 8 x10 watt speakers safely. Be aware of 
this booby trap. Always plan to have 20% 
more power than you think you will need. 

2. Incorrect output connection: If you ac-

cidentally connect your terminal strip 
on the amplifier to the 8 ohm output 
instead of the 100/70V line, you will have 
distortion and risk damaging the amplifier..

3. Short circuits and no circuits: Check that 

your wiring has not been accidentally cut, 
miss-connected or generally damaged 
in the course of installation. This can be 
common with building sites with multiple 
trades people installing equipment into the 
same ceiling cavities as the audio system.

Operation

After all connections are completed, turn on 
the power.  If necessary, turn the gain control 
on the rear panel to what you desire. We 
suggest turning the gain level to maximum 
always.

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.

• 

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 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. 

Содержание QTA 2120P

Страница 1: ...Q Tech Q Tech Commercial Series QTA 2120P 2240P 2 Channel Power Amplifiers User Manual ...

Страница 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...

Страница 3: ...Tech Commercial Series QTA 2120P 2240P 1 Contents Introduction 2 Description 2 Front Panel Layout 3 Rear Panel Layout 3 Power Source 4 Main Connections 4 Installation Practice 4 Operation 5 Trouble Shooting 5 Specifications 6 Technical Notes 6 ...

Страница 4: ...llation is completed with the same attention to detail your amplifier will deliver its best results Please read 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 d...

Страница 5: ... Terminal 8 Channel 2 XLR Input 3 Channel 2 Speaker Terminal 9 Channel 1 Link Output 4 Channel 1 Speaker Terminal 10 Channel 1 Phone Jack Input 5 24v DC Power Input 11 Channel 1 XLR Input 6 Channel 2 Link Output 1 Power On Off Switch 4 Signal Indicators 2 Power On Indicator LED 5 Peak Indicators 3 Channel Volume Controls 6 Protection Indicators 7 6 5 8 9 10 11 1 2 3 4 1 2 4 5 6 3 ...

Страница 6: ...ce 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 speaker transformer and the other strip wire to the required voltage taping Step 3 Take a second piece of figure 8 cable and connect the plain ...

Страница 7: ...in the course of installation This can be common with building sites with multiple trades people installing equipment into the same ceiling cavities as the audio system Operation After all connections are completed turn on the power If necessary turn the gain control on the rear panel to what you desire We suggest turning the gain level to maximum always Trouble Shooting If the amplifier fails to ...

Страница 8: ...ut can be quite involved but there is a simple technique for not overloading the amplifier As for the amplifiers there are two common standards 100 Volt line in Europe and Asia and 70 Volt line on the American continent For the purpose of simple calculations we will use the European standard for this exercise On the rear of a 70 100V amplifier you will find an output terminal strip This terminal s...

Страница 9: ...heating 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 similar problem would be trying to draw 2 000 watts from a 1 000 watt generator Sooner or later Expect a system failure Let us take a 100 watt amplifier If you have 20 speakers and you set them at the 5 w...

Страница 10: ...KΩ 10W 1KΩ 40W 250Ω 0 5W 20KΩ 15W 667Ω 50W 200Ω 1W 10KΩ 20W 500Ω 75W 133Ω 2W 5KΩ 25W 400Ω 100W 100Ω 3W 3 33KΩ 30W 333Ω 150W 66 7Ω 5W 2KΩ 35W 286Ω 200W 50Ω 100V plan P E x E Z 100x100 Z 10 000 Z P Power W Z Impedance Ω E 100V Designed voltage of a general use amplifier High impedance of speakers and output calculation table for 100Volt systems ...

Страница 11: ......

Страница 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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