PA Stereo Amplifier
These instructions are intended for users without
any specific technical knowledge . The speakers,
however, should only be connected by persons
with the corresponding technical knowledge .
Please read these instructions carefully prior to
operating the unit and keep them for later ref-
erence .
All operating elements and connections
described can be found on the fold-out page 3 .
1
Operating Elements and
Connections
1.1 Front panel
1 Volume control for the left channel L-CH
2 Status LEDs for the left channel:
PROTECT lights up with activated protective
circuit (the connection to the speakers is
separated):
1 . after switching-on for a short time
2 . in case of overload/overheating (e . g . also
by short circuit at the output)
3 . in case of DC voltage at the output
LIMITER lights up when the input signal is
too high and limited by the limiter
ACTIVE lights up as a power indication
−25 dB, −20 dB, −15 dB show the input level
3 LC display for operating mode and temper-
atures
4 Status LEDs for the right channel (
5 Volume control for the right channel R-CH
6 POWER switch
1.2 Rear panel
7 Balanced inputs: XLR jacks for the left chan-
nel (L-CH) and the right channel (R-CH)
8 XLR feed-through outputs to pass on the
input signals e . g . to an additional amplifier
9 Switch FILTER with three positions
SUBWOOFER: low pass filter
with −6 dB at 120 Hz
SATELLITE:
high pass filter
with −6 dB at 120 Hz
FULLRANGE: no filter
10 DIP switches for selecting the operating
mode and for separating signal ground and
housing ground:
operating mode STEREO
operating mode PARALLEL
operating mode BRIDGE
signal ground connected to
housing ground
signal ground and
housing ground s eparated
(groundlift)
11 Protective switch to protect the unit; to reset
the released switch, press down the button
12 Speaker output R-CH for the right channel:
Speakon jack
13 Speaker output L-CH for the left channel:
Speakon jack
14 PowerCon mains jack for connection to a
socket (230 V/ 50 Hz)
Important: The PowerCon plug-in connec-
tion must not be connected or
6
15 Speaker output BRIDGE: Speakon jack for
bridge mode
2
Safety Notes
The unit corresponds to all relevant directives of
the EU and is therefore marked with
WARNING The unit is supplied with hazard-
ous mains voltage . Leave servic-
ing to skilled personnel only and
do not insert anything 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 and splash
water, high air humidity, and heat (admissible
ambient 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 off by air circulation . Therefore, the
air vents at the housing must not be covered .
•
Do not set the unit into operation, and im-
mediately disconnect the mains plug from the
mains socket if
1 . there is visible damage to the unit or to the
mains cable,
2 . a defect might have occurred after a drop
☞
item 2)
or similar accident,
3 . malfunctions occur .
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 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 operation
definitively, take it to a local recycling
plant for a disposal which will not be
harmful to the environment .
3
Applications
This PA stereo amplifier has especially been de-
signed for stage and disco applications . The am-
plifier may be operated in stereo mode, in mono
parallel mode, or in mono bridge mode . With its
class H output circuit, it operates more efficiently
than standard amplifiers of class AB technology .
Due to a switchable filter, the amplifier may
also be used only for subwoofers or only for the
frequency range exceeding 120 Hz . Extensive
protective circuits protect the amplifier and the
speakers connected . Two powerful, tempera-
ture-controlled fans supply the necessary cooling
of the amplifier .
4
Setting-Up
The amplifier is provided for installation into a
rack (482 mm / 19"), but it may also be used as a
table top unit . In each case air must be allowed
to flow freely through all ventilation vents so
that a sufficient cooling is ensured .
disconnected when carrying
any voltage or load . (Switch off
the unit beforehand!)
.
4.1 Rack installation
For rack mounting, 3 RS (rack spaces) = 133 mm
are required . The heated air blown out by the
amplifier at the rear must be able to dissipate
from the rack, otherwise a heat accumulation
will occur in the rack which may not only dam-
age the amplifier but also other units in the rack .
In case the heat is not dissipated sufficiently, a
fan unit has to be inserted into the rack .
To prevent top-heaviness of the rack, the
amplifier must be inserted in the lower part of
the rack . To ensure a safe fixing, the front panel
alone is not sufficient . In addition, the unit must
be fastened at the rear side or be supported by
means of lateral rails or a bottom plate .
5
Connecting the Amplifier
All connections must only be made or changed
with the unit switched off!
5.1 Inputs
Connect the output of a preamplifier or mixer
to the XLR jacks INPUTS (7) .
– The jacks are designed for balanced signals;
the pin configuration is shown in fig . 2 . For
connection of sources with unbalanced sig-
nals, use an adapter with the XLR contacts 1
and 3 bridged (e . g . the adapter MCA-15 / 2
from IMG STAGELINE: 2-pole 6 .3 mm inline
jack to XLR plug) .
– The input signal should have line level . For
rated power of the amplifier, an input signal
of 1 V is required as a minimum .
– For bridge mode or parallel mode, only connect
the input of the left channel L-CH .
– Via the feed-through outputs (8) which are
directly connected to the respective input
jack (7), the signal can be fed e . g . to an addi-
tional amplifier .
5.2 Speakers
The maximum output power is reached in stereo
mode and in parallel mode when connecting 4 Ω
speakers (minimum admissible load impedance) .
It is also possible to connect 8 Ω speakers, how-
ever, in this case the output power will slightly
decrease . In bridge mode, the maximum out-
put power will be reached with an 8 Ω speaker
(minimum admissible load impedance in bridge
mode) . The required power rating (P
speakers is listed in the table fig . 3 .
As long as in stereo or parallel operation
the RMS output power of 1250 W per channel
is not exceeded, the operation with 2 Ω load
is possible . A bridge operation at a 4 Ω load is
possible up to an RMS output power of 2500 W .
Connect the speakers to the Speakon jacks .
Fig . 2 shows the pin configuration of the plug;
the contact pairs 1+/1− and 2+/2− are connected
in the unit with each other in each case .
After connecting a Speakon plug to the jack,
turn it clockwise until it locks . For removing it
later, retract the latch lock at the plug and turn
the plug counter-clockwise .
When connecting the speakers, pay atten-
tion to the same polarity of all speakers .
For stereo mode or parallel mode connect
the speakers to the Speakon jacks L-CH (13)
and R-CH (12) . For bridge mode, connect the
speaker to the Speakon jack BRIDGE (15) .
Table fig . 3 also shows possibilities of con-
nection for several speakers to one output . In
each case it is stated which power rating (P
each speaker must have as a minimum with the
corresponding impedance (Z) . When intercon-
) of the
min
)
min