Operation; Protective Circuits - Monacor PA-1242 Bedienungsanleitung

4.1.2 8 Ω speaker or speaker group
with a total impedance of 8 Ω
Figs . 5 to 8 show different possibilities to
reach an 8 Ω impedance with corresponding
speakers . Con nect the speakers to the termi-
nals COM and 8 Ω (9) . Observe the correct
polarity (positive and negative connections as
shown in figs . 5 to 8) . The positive connec-
tion of the speaker cables is always specially
marked .
4.2 Input
For optimum level control, a signal of +4 dBu
= 1 .2 V is required . The signal source should
have a bal anced connection via the XLR jack
(13) or the screw connections (15) . Thus,
an optimum interference suppression is ob-
tained .
If the output of the signal source is un-
balanced (e g . in case of phono jacks), use
a corresponding adapter (e . g . NA-2MPMF
from MONACOR) for connection via the XLR
jack, or, when using the screw connections,
connect the terminal to the terminal GND,
connect the signal to and the ground to
GND .
Specifications
RMS output power
THD
Speaker outputs
Output impedance
100 V
70 V
25 V
Input
Sensitivity
Impedance
Wiring
Frequency range
High-pass filter (to be switched)
S / N ratio
Ambient temperature
Power supply
Mains voltage
Power consumption
Emergency power supply
DC consumption
Dimensions (W × H × D)
Weight
Subject to technical modification .
4.3 Feed-through output
For parallel connection of a further PA am-
plifier, the feed-through output LINK can be
used via the XLR jack (14) or via the screw
connections (16) . Connect the output LINK to
the input of the second PA amplifier .
4.4 Power supply and
emergency power supply
1) Finally connect the supplied mains cable
to the mains jack (8) first and then to a
socket (230 V/ 50 Hz) .
2) For continuous operation of the amplifier
in case of a possible mains failure, connect
a 24 V emergency power supply unit (e . g .
PA-24ESP from MONACOR) to the termi-
nals DC POWER (7) . With a cable length of
up to 4 m, a cable cross section of 5 mm
is required as a minimum .
Note: If the 24 V voltage from the emergency power
unit is present at the terminals DC POWER, the ampli-
fier cannot be switched off with the switch POWER
(6) . In case of a mains failure or if it is switched off,
it switches automatically to the emergency power
supply .
PA-1242
240 W
< 1 %
100 V, 70 V, 25 V or 8 Ω
42 Ω
20 Ω
2,6 Ω
+4 dBu (1,2 V)
30 kΩ
balanced
35 – 20 000 Hz, −3 dB
400 Hz, 6 dB / oct .
> 100 dB (A weighted)
0 – 40 °C
230 V/ 50 Hz
750 VA
24 V⎓
max . 20 A
482 × 89 × 374 mm, 2 rack spaces
12 .5 kg
All rights reserved by MONACOR
may be reproduced in any form or by any means for any commercial use.

5 Operation

1) First put the LEVEL control (1) to the po-
sition "0" .
2) Switch on the amplifier with the button
POWER (6) . The green operating LED PWR
(3) lights up .
3) Adjust the LEVEL control (1) to the desired
volume value . In case of overload, the red
LED CLIP of the level LEDs (2) lights up .
In this case, reduce the volume with the
control .
4) To improve the speech intelligibility, a
high-pass filter (400 Hz, 6 dB / oct .) can
be switched on with the button 400 Hz
(12) . In case of doubt, the button should
be pressed . Thus, low frequency interfer-
ence is suppressed .
2

6 Protective Circuits

At the input, the amplifier is protected against
rumble noise by a 30 Hz high-pass filter and
against high frequency interference by a 30
kHz low-pass filter . Further circuits serve as a
protection against overload and overheating .
If the protective circuit is activated, the LED
PROT (4) lights up and the amplifier is muted:
1 . for approx . 1 second after switching on
(switch-on delay)
2 . for approx . 1 second after switching off
3 . in case of overload of the amplifier
4 . in case of overheating of the amplifier; the
LED TEMP (5) lights up additionally
If the LED PROT lights up during operation
or if it does not extinguish after switching
on, switch off the amplifier and eliminate the
source of error .
PA-1480
480 W
< 1 %
100 V, 70 V, 25 V or 8 Ω
21 Ω
10 Ω
—
+4 dBu (1,2 V)
30 kΩ
balanced
35 – 20 000 Hz, −3 dB
400 Hz, 6 dB / oct .
> 100 dB (A weighted)
0 – 40 °C
230 V/ 50 Hz
1400 VA
24 V⎓
max . 40 A
482 × 89 × 374 mm, 2 rack spaces
17 .5 kg
® INTERNATIONAL GmbH & Co. KG. No part of this instruction manual
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