PA Mixing Amplifier
These instructions are intended for the installer
of the unit with knowledge in 100 V or 70 V
PA technology . Please read the operating in-
structions carefully prior to operating the unit
and keep them for later reference . All operat-
ing elements and connections described can
be found on the fold-out page 3 .
1 Control Elements and
Connections
1.1 Front panel
1 Mounting bracket (2 x) to install the unit
into a rack
2 LEDs to indicate the output level
3 Overload indicator CLIP
4 Overheat indicator PROT
5 Power indicator ON
6 Mixing controls to adjust the volume for
the channels CH 1 to CH 3
7 Tone controls BASS and TREBLE
8 Control MASTER to adjust the total volume
9 POWER switch
Note: It will not be possible to switch off the am-
plifier when a 24 V DC voltage of an emergency
power supply unit is available at the terminals
DC INPUT (13) .
1.2 Rear panel
10 Jack for the mains cable provided for con-
nection to a mains socket (230 V/ 50 Hz)
11 Support for the mains fuse
Always replace a blown fuse by one of the
same type!
12 Protective cover for the screw terminals
Never operate the unit without the protec-
tive cover:
☞
Warning in chapter 6
13 Screw terminals* DC INPUT for connection
of an emergency power supply unit (⎓ 24 V)
14 Screw terminals* SPEAKER OUTPUT for
connection of the speakers:
☞
chapter 5 .1 and figures on page 3
15 Screw terminals* EXT . PRIO . to connect a
muting switch
16 DIP switches PRIORITY to set the priority
for the input channels:
chapter 5 .3 and table (fig . 9)
☞
17 Control MUTE to define the level of vol-
ume attenuation for the channels whose
volume is attenuated by means of priority
switching
for each of the channels CH 1 to CH 3:
18 Channel input (combined XLR /6 .3 mm
jack, balanced) for connection of an audio
source (either a microphone or a unit with
line signal level)
19 Button PHANTOM POWER to activate the
24 V phantom power supply for the respec-
tive channel
Observe the notes in chapter 5 .2 .
20 Control GAIN to match the input sensiti-
vity of the respective channel to the audio
source connected
* To make handling easier, the screw terminals can be
removed from their plug-in connection .
6
2 Safety Notes
The unit corresponds to all relevant directives
of the EU and is therefore marked with
WARNING The unit uses dangerous mains
voltage . Leave servicing to skilled
personnel and do not insert any-
thing into the air vents; inexpert
handling may result in electric
shock .
•
The unit is suitable for indoor use only . Pro-
tect it against dripping water, splash water
and high air humidity . The admissible ambi-
ent temperature range is 0 – 40 °C .
•
Do not place any vessels filled with liquid,
e . g . drinking glasses, on the unit .
•
The heat generated inside the unit must be
dissipated by air circulation; never cover the
air vents of the housing .
•
Immediately disconnect the unit from the
power supply
1 . if the unit or the mains cable is visibly
damaged,
2 . if a defect might have occurred after the
unit was dropped or suffered a similar
accident,
3 . if malfunctions occur .
In any case the unit must be repaired by skil-
led personnel .
•
Never pull the mains cable to disconnect the
mains plug from the mains socket, always
seize the plug .
•
For cleaning only use a dry, soft cloth; never
use water or chemicals .
•
No guarantee claims for the unit and no
liability for any resulting personal damage
or material damage will be accepted if the
unit is used for other purposes than originally
intended, if it is not correctly connected or
operated, or if it is not repaired in an expert
way .
If the unit is to be put out of oper-
ation definitively, take it to a local
recycling plant for a disposal which
is not harmful to the environment .
3 Applications
This mono mixing amplifier is specially de-
signed for PA systems operating with 100 V or
70 V technology . However, it is also possible
to use low-impedance speakers instead of
100 V or 70 V speakers .
The amplifier is equipped with three
mixable input channels for the connection of
microphones (incl . phantom-powered micro-
phones) or units with line signal level . Priority
for the channels can be set by means of the DIP
switches . In addition, it is possible to connect
an emergency power supply unit (⎓ 24 V) and
a switch for muting the amplifier . Protective
circuits against overload, short circuit and over-
heating are integrated in the amplifier .
4 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") . Two M4 threads at the bot-
tom of the housing allow the amplifier to be
mounted to wall mounting brackets .
In order to ensure sufficient cooling of the
.
amplifier, air must always be able to flow freely
through all air vents .
4.1 Installation into a rack
In the rack, two rack spaces are required (1 rack
space RS = 44 .45 mm) . Screw the two mount-
ing brackets supplied (1) to the sides of the unit
(fig . 1) and then install the unit into the rack .
For a safe installation of the amplifier, lateral
rails or a bottom plate are recommended .
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 dissipation,
install a ventilation unit into the rack .
5 Installing the Amplifier
The amplifier should only be installed by skilled
personnel!
WARNING During operation, there is a haz-
ard of contact with a dangerous
voltage of up to 100 V at the
speaker terminals (14) . Always
switch off the PA system prior to
making any connections!
To gain access to the screw terminals (13, 14
and 15) and to the priority control elements
(16, 17), remove the protective cover (12) . To
make sure that nobody accidentally touches
the speaker terminals during operation, always
screw the protective cover onto the unit when
the connections and settings have been made .
To make handling easier, the screw ter-
minals can be removed from their plug-in
connection .
5.1 Connecting speakers
Either 100 V speakers or 70 V speakers or
low-impedance speakers can be connected .
Never connect a combination of these three
speaker types .
Use the appropriate terminals SPEAKER OUT-
PUT (14), depending on the speaker type:
− Connect 100 V speakers to "100V" and
"COM" (admissible total load by the
speakers: 60 W RMS max.) .
The connection is shown in fig . 3 .
− Connect 70 V speakers to "70V" and "COM"
(admissible total load by the speakers:
60 W RMS max.) .
The connection is shown in fig . 4 .
− Connect low-impedance speakers to
"4 −16Ω" and "COM" (admissible total
impedance of the speakers: 4 Ω min.) .
Figure 5 shows the connection of a single
speaker with an impedance of 4 Ω, 8 Ω
or 16 Ω . Figures 6 to 8 show various options
of how to meet the minimum impedance of
4 Ω when multiple speakers are connected;
please note that other options are possible .
Always observe the correct polarity when ma-
king the connections . The terminal COM is the
negative pole .