Setting Up The Amplifier; Connections And Settings - Monacor PA-924 Manual De Instrucciones

4 Installation
The amplifier should only be installed by
skilled personnel!

4.1 Setting up the amplifier

The amplifier can be set up on its own or
installed in a rack for units with a width of
482 mm (19") . In order to ensure sufficient
cooling of the amplifier, air must always be
able to flow freely through all air vents .
4.1.1 Installation into a rack
Screw the two mounting brackets (1) pro-
vided to the sides of the unit . In the rack,
2 rack spaces (for model PA-924) or 3 rack
spaces (for model PA-948) are required . To
prevent the rack from becoming top-heavy,
insert the amplifier into the lower section
of the rack . The mounting brackets are not
sufficient for fixing the amplifier safely; addi-
tionally use lateral rails or a bottom plate to
secure the amplifier .
The hot air given off by the amplifier must
be dissipated from the rack; otherwise, heat
will accumulate in the rack which may not
only damage the amplifier but also other units
in the rack . In case of insufficient heat dissi-
pation, install a ventilation unit into the rack .

4.2 Connections and settings

WARNING During operation, there is a
hazard of contact with a dan-
gerous voltage of up to 100 V
at the speaker terminals (15) .
Always switch off the PA sys-
tem prior to making any con-
nections!
4.2.1 Connecting speakers
Either 100 V speakers (or 70 V or 50 V speak-
ers) or low-impedance speakers can be con-
nected . Never connect a combination of these
speaker types .
Use the appropriate terminals SPEAKER OUT-
PUT (15), depending on the speaker type:
− Connect 100 V speakers to "100V" and
"COM": fig . 3
☞
(70 V speakers to "70V" and "COM";
50 V speakers to "50V" and "COM:
figs . 4 and 5, respectively)
☞
The admissible load by the speakers is
240 W RMS max. (PA-924) and
480 W RMS max. (PA-948) respectively .
− Connect low-impedance speakers to "4Ω"
and "COM" . The total impedance of the
speakers must not be less than 4 Ω .
Figures 6 to 9 show various options of how
to meet the minimum impedance of 4 Ω;
please note that other options are possible .
Always observe the correct polarity when
making the connections . The terminal COM
is the negative pole .
To make handling easier, the screw terminal
strip can be removed from its plug-in con-
nection .
8
4.2.2 Audio sources for the channels 1 – 4
Each of the channels 1 to 4 provides an XLR
jack (21) for the connection of a microphone
or mono audio source with line signal level
(e . g . mono output of a mixer) . The jack is bal-
anced; however, by means of an appropriate
adapter such as the audio cable MCA-158
(RCA  XLR) from MONACOR, it can also be
used for an unbalanced connection .
Use the control GAIN (22) of the respec-
tive channel to match its input sensitivity to
the output level of the audio source: When
a microphone is connected, turn the control
clockwise; when an audio source with line
level is connected, turn the control anti-
clockwise . If required, readjust the control
GAIN after the amplifier has been set into
operation: When the mixing control (5) of the
channel must be turned back very far (sound
too loud or distorted) or turned up very far
(sound too low) to set the volume desired,
turn the control GAIN anti-clockwise or clock-
wise accordingly .
Phantom power supply
To activate the 48 V phantom power supply
for a channel (e . g . when a condenser mi-
crophone is connected), set the appropriate
switch PH .PWR (20) to "ON" . When the
phantom power supply has been activated,
the corresponding LED +48 V (19) will light
up .
ATTENTION
1 . Only actuate the switch when the am-
plifier is switched off (switching noise) .
2 . Only activate the phantom power supply
when a phantom-powered audio source
is connected; audio sources not designed
for phantom power supply (e . g . micro-
phone with unbalanced output) may be
damaged .
4.2.3 Audio sources for the AUX channel
The amplifier provides four inputs (23) for the
connection of stereo audio sources with line
signal level (e . g . tuner, CD / MP3 player, PC) .
During operation, use the appropriate button
(2) on the front panel to select the desired
input for the AUX channel .
Connect each of the units to a pair of
RCA jacks L / R . In the amplifier, the signals
of the two stereo channels will be mixed to
a mono signal .
4.2.4 Priority function
The DIP switches 1 to 4 (12) can be used to
give the individual channels 1 to 4 priority
over the AUX channel (corresponding DIP
switches set to "ON") . The volume of the
AUX channel will be substantially attenu-
ated as soon as a signal (e . g . a microphone
announcement) is available on a channel of
higher priority .
4.2.5 Pushbutton for chime triggering
A chime can be triggered by means of a con-
nected pushbutton . Connect the pushbutton
to the terminals CHIME REMOTE (16) .
Setting the chime
After switching on the amplifier, use the
switch CHIME (11) to select the type of chime
desired ("2T" = 2-tone chime, "4T" = 4-tone
chime) and then use the control CHIME VOL-
UME (13) to adjust the volume of the chime .
4.2.6 Audio processing unit
Use the RCA jacks PRE OUT and AMP IN
(25) to insert an audio processing unit (e . g .
equalizer, effect unit): The mixed signal will
be routed to the audio processing unit via
PRE OUT, processed and then returned to the
amplifier via AMP IN .
1) Remove the jumper connecting the jacks
PRE OUT and AMP IN .
2) Connect the input of the unit to be in-
serted to the output PRE OUT .
3) Connect the output of the unit to be in-
serted to the input AMP IN .
Note: When removing the unit inserted, remem-
ber to connect PRE OUT and AMP IN by means
of the jumper; otherwise, the signal flow will be
interrupted .
4.2.7 Additional amplifier and recorder
The XLR output MIX OUT (14) can be used to
connect an additional amplifier (or a different
subsequent audio unit) . Connect the output
to a balanced line level input .
The output REC (24) is suitable for the
connection of a recorder . For the connection
of a stereo unit, two jacks L / R are available .
The amplifier is monophonic; therefore, the
signals at the two jacks are identical .
The adjustment of the control MASTER (8)
will have no influence on the output signal
of MIX OUT and REC .
4.2.8 Power supply and
emergency power supply
1) To ensure continued operation of the am-
plifier after a mains failure, connect the
terminals DC INPUT (10) to an emergency
power supply unit (⎓ 24 V), e . g . the emer-
gency power supply unit PA-24ESP from
MONACOR .
Notes:
1 . When ⎓ 24 V is available at the terminals
DC INPUT, the amplifier will be in operation
even when the switch POWER (9) has been
set to "Off" . When both the emergency
power supply and the mains power supply
are available, the switch POWER will switch
between these two power supplies .
2 . With emergency power supply, the ampli-
fier will provide less power than with mains
power supply .
2) Finally, first connect the mains cable pro-
vided to the mains jack (17) and then to a
mains socket (230 V/ 50 Hz) .