Quest Engineering QTA1120P User Manual - Operation
QTA-
1120P/1240P
User Manual
User Manual
Q-Tech Commercial Series
QTA-1120P/1240P
5
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.
Please ensure the switch is on the Mono
position when you are not connecting to
another 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 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 wire to the parallel
COM connection and the other + (stripe) wire
to the parallel output from the transformer
terminal block and connect it in the same way
to the next ceiling speaker.
Step 4 .
Continue this process until all the
ceiling speakers are connected in a parallel
connection with all the COM connections
and all the wattage connections following a
parallel connection.
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.