16
English
4 Setup Options
The amplifier is designed for installation into a rack (483 mm/19”), but
can also be placed on a flat surface . To ensure sufficient cooling of the
amplifier, air must always be able to flow freely through all air vents .
4.1 Rack installation
For rack installation, 2 rack spaces (89 mm) are required . To prevent
the rack from becoming top-heavy, insert the amplifier into the lower
section of the rack . The front plate is not sufficient for fixing the am-
plifier safely; additionally 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 dissipation, install a ventilation unit into the rack .
5 Connecting the Amplifier
Before making or changing any connections, switch off all units (ex-
ception: USB port) .
5.1 Audio source
It is possible to connect two mono audio sources or a stereo audio
source with line output level, e . g . mixer, preamplifier, CD player .
Connect the output of the audio sources to the XLR jacks CH A IN and
CH B IN (8) . The jacks are balanced . Audio sources with unbalanced
output can be connected via an adapter where the XLR contacts 1
and 3 are bridged . The XLR jacks LINK OUT (9) are connected to the
corresponding input jack and are used to route the signal to another
amplifier, for example .
5.2 Speakers
Connect the speakers (minimum impedance: 4 Ω) to the Speakon-com-
patible speaker jacks (12) .
Then turn the speaker plug clockwise until it engages . To re-
move the plug, pull back the latch on the plug and turn the plug
anti-clockwise .
The power rating of the speakers should generally not be lower
than the output power of the amplifier (
☞
chapter 10); otherwise,
it is recommended to limit the output power accordingly in order to
protect the speakers (
☞
chapters 6 .3 .8 and 7 .4 .5) .
5.2.1 Bridge mode
The bridge mode is used to obtain more power at a single speaker . In
the bridge mode, the two amplifier channels are combined to a mono
amplifier: Select the operating mode BRIDGE (
☞
chapters 6 .2 .2 and
7 .4 .1) . The input signal at channel A will now be inverted before it
is additionally sent to channel B . Thus, the voltage at the output will
be doubled when the speaker is connected to the jack BRIDGE (11) .
Signals at the input CH B IN will be ignored .
In the bridge mode, the minimum impedance of the speaker must
be 8 Ω .
5.2.2 Connecting multiple speakers to a single channel
Examples of how to operate multiple speakers at a single output can
be found in the table on page 2 . The table lists the nominal imped-
ance Z and the minimum rated power P
min
of the individual speakers .
5.3 Computer
For remote control of the amplifier via a computer, connect the com-
puter to the jack PC CONTROL (6) by means of a USB cable .
5.4 Power supply
For power supply, connect the mains cable provided to the mains
jack (13) and then to a mains socket (230 V/ 50 Hz): Connect the blue
Powercon plug of the mains cable to the mains jack and then turn it
clockwise until it engages . To remove the plug, pull back the latch on
the plug and turn the plug anti-clockwise .
Important:
Never connect or disconnect a Powercon plug while voltage is applied .
Always make the Powercon connection before making the mains connection .
When disconnecting, always disconnect the mains connection before discon-
necting the Powercon connection .
6 Operation
CAUTION:
The volume is digitally adjusted by means of the rotary
knobs (2, 5) or by remote control via the USB interface; it cannot be
changed or read before the unit is switched on . Therefore, the signal
sources should be switched off for the time being when the initial
adjustment of the amplifier at switch-on is not known .
Use the POWER switch (7) to switch on the amplifier . First, the LC
display (3) will show a welcome message; then the main display with
the following information, for example, will appear:
Mode:ST 1FLAT
-20dB -20dB
Fig. 5 Main display
Mode:ST
The operating mode is “Stereo” .
1FLAT
The name of the current configuration is FLAT; it uses
storage location 1 .
-20dB
Input signal attenuation (volume adjustment) for channels
A and B is set to −20 dB .
The volume for channel A can be changed with the rotary knob
CH A (2), the volume for channel B can be changed with the rotary
knob CH B (5) . Like all other settings, this change must be saved; other-
wise it will be lost when the amplifier is switched off (
☞
chapter 6 .3 .9) .
CAUTION
Never adjust a very high volume .
Permanent high volumes may damage your hearing!
Your ear will get accustomed to high volumes which do
not seem to be that high after some time . Therefore,
do not further increase a high volume after getting
used to it .
6.1 Password protection
The amplifier provides a password protection feature to prevent un-
authorized operation: To make changes to any settings (with the
exception of the volume settings directly at the unit), the user must
enter the correct password . The password is a four-digit number; it
is factory-set to
8888
.
Change this password to increase security (
☞
chapters 6 .3 .10 and
7 .3 .5) . When no operation is made, the amplifier will be automatically
locked after a few minutes and the password must be re-entered .
6.2 Signal processing configuration
ATTENTION
The signal processor is an effective tool for making very
detailed but also major changes to the transmission
properties of the PA system . Therefore, each modifica-
tion to the parameters should be made with care and
expertise . At the worst, extreme changes to the settings
may damage the speakers .
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