INPUT
1
0
10
1
PA Mixing Amplifier
Please read these instructions carefully prior to
operation and keep them for later reference .
Connection of the speakers (chapter 5 .1)
requires adequate technical knowledge in 100 V
PA technology and is to be made by experts
only . Operation of the amplifier is easy, even
for adults without any expert knowledge . How-
ever, in case of any queries, please contact your
installer or retailer .
1
Operating Elements
and Connections
1.1 Front panel
1 Input level controls for the mono channels
IN PUT 1 to INPUT 4
2 Input level control for the AUX channel
3 Tone controls
BASS control
±10 dB / 100 Hz
TREBLE control ±10 dB / 10 kHz
4 Control MASTER VOLUME for the total
volume
5 POWER LED
6 Level indicators
7 POWER switch
1.2 Rear panel
8 Mains jack for connection to a mains socket
(230 V/ 50 Hz) via the supplied mains cable
9 Support for the mains fuse;
replace a blown fuse only by one of the
same type
10 Clamping screw for a possible ground con-
nection (e . g . in case of hum problems)
11 Terminals* for an emergency supply voltage
(⎓ 24 V)
12 Terminals* for the connection of the
speakers
13 XLR input jacks of the mono channels
INPUT 1 to INPUT 4 for connecting micro-
phones or mono units with line output
Caution! With phantom power activated
[corresponding DIP switch (20) in the lower
position], the XLR jacks are supplied with
20 V phantom power . In this case, no un-
balanced microphones or audio units must
be connected as they may be damaged .
14 Feed-through connections PRE OUT and
AMP IN for inserting a unit (e . g . equalizer);
the output level of jack PRE OUT is inde-
pendent of control MASTER VOLUME (4)
* The screw terminals can be removed from their
plug-in connections for better handling .
6
INPUT
INPUT
INPUT
2
3
4
0
10
0
10
0
10
PA-900 PA MIXING AMPLIFIER 120 W
15 Output LINE OUT for connection of further
amplifiers;
the output level is independent of control
MASTER VOLUME (4)
16 Input AUX IN for the connection of audio
units, e . g . CD player, tuner, cassette re-
corder, etc .
17 Selector switches for the mono channels
INPUT 1 – 4 between microphone level
(button not pressed) and line level (button
pressed)
18 Terminals for connecting a microphone or
an audio unit with line output; connected
in parallel to the XLR jack INPUT 1
19 Button AUTOTALK for switching on / off the
talk over function of channel 1
20 DIP switches +21 V PHANTOM POWER for
switching on the 20 V phantom power for
the XLR jacks INPUT 1 to INPUT 4 (13);
required for connect ing capacitor or elec-
tret microphones operating with phantom
power
Caution! Only actuate the switches with
the amplifier switched off to avoid swit-
ching noise . Please observe the note under
item 13 .
2
Safety Notes
The unit corresponds to all relevant directives of
the EU and is therefore marked with
WARNING The unit is supplied with haz-
During operation, there is a hazard of contact
at the speaker connections (12) with a dan-
gerous voltage up to 100 V . Always switch of
the PA system before making or changing any
connections .
Do not insert anything into the air vents! This
could result in an electric shock .
•
The unit is suitable for indoor use only . Protect
it against dripping water and splash water,
high air humidity, and heat (admissible am-
bient temperature range 0 – 40 °C) .
•
Do not place any vessels filled with liquid, e . g .
drinking glasses, on the unit .
•
The heat being generated in the unit must be
dissipated by air circulation . Therefore, never
cover the air vents .
•
Do not set the unit into operation, and im-
mediately disconnect the mains plug from the
mains socket if
AUX
BASS
TREBLE
0
10
–10
+10
–10
+10
dB
dB
2
3
.
ardous mains voltage . Leave
servic ing to skilled personnel
only . Inexpert handling may
cause an electric shock hazard .
MASTER
POWER
VOLUME
+ 3
0 dB
– 3
– 8
–13
0
10
ON
4
5 6
1 . there is visible damage to the unit or to the
mains cable,
2 . a defect might have occurred after a drop
or similar accident,
3 . there are malfunctions .
The unit must in any case be repaired by skilled
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 chemicals or water .
•
No guarantee claims for the unit and no liabil-
ity for any resulting personal damage or mate-
rial damage will be accepted if the unit is used
for purposes other than originally intended, if
it is not correctly connect ed or operated or if
it is not repaired in an expert way .
If the unit is to be put out of operation
defini tively, take it to a local recycling
plant for disposal which is not harmful
to the environment .
3
Applications
The amplifier has especially been designed for
use in PA systems . It can deliver 120 W RMS to
100 V and 70 V speakers or to a speaker group
with a total impedance of 4 Ω . Microphones
(channels 1 – 4) or units with line level (channels
1 – 4 and AUX) can be connected to the five
input channels which can be mixed with one
another . Channel 1 is equipped with a talkover
function which attenuates the volume of the
other channels by 40 dB in case of an announce-
ment .
4
Setting up the Amplifier
The amplifier has been designed for installation
into a rack (482 mm / 19"), however, it can also
be used as a table top unit . In any case, air must
be allowed to pass freely through all air vents to
ensure sufficient cooling of the power amplifier .
4.1 Rack installation
For rack installation, screw the two supplied
mount ing brackets to the sides of the unit . In
the rack, 2 rack spaces are required for the am-
plifier (1 rack space = 44 .45 mm) .
To prevent top-heaviness of the rack, the
amplifier must be inserted into the lower part
of the rack . The front panel alone will not be
able to secure the unit . Side rails or a base plate
must additionally be provided .
®
7
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