Class D PA Amplifier
These instructions are intended for installers
with specific knowledge in 100 V technology
for PA applications . Please read the instruc-
tions carefully prior to installation and keep
them for later reference .
All operating elements and connections
described can be found on the fold-out
page 3 .
1 Overview
1 Signal LEDs for each channel pair
PROT lights up to indicate activation of
the protective circuit for a channel
pair
CLIP lights up to indicate overload of a
channel pair
2 Button MUTE to mute the corresponding
channel
3 Volume control LEVEL for each channel
4 POWER switch
5 Balanced inputs (XLR jacks) for each
channel
6 Unbalanced inputs (RCA jacks) for each
channel
7 Protective covers for the speaker termi-
nals
WARNING Never operate the ampli-
fier without the covers . If
you touch the terminals,
you may get an electric
shock .
8 Speaker terminals
9 Support for the mains fuse
Always replace a blown fuse by one of
the same type!
10 Mains jack for connection to a socket
(230 V/ 50 Hz) via the mains cable pro-
vided
11 Screw terminals 24 V for an emergency
power supply
2 Safety Notes
This unit corresponds to all relevant direc-
tives of the EU and is therefore marked
with
.
WARNING The unit uses dangerous
mains voltage . Leave servicing
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 .
Protect it against dripping water and
splash water, high air humidity and heat
(admissible ambient temperature range:
0 – 40 °C) .
•
Do not place any vessel filled with liquid
on the unit, e . g . a drinking glass .
•
The heat produced inside the unit must
be dissipated by air circulation . Therefore,
never cover the air vents of the housing .
6
•
Do not operate the unit and immediately
disconnect the mains plug from the socket
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
skilled personnel .
•
Never pull the mains cable to disconnect
the mains plug from the 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 orig-
inally intended, if it is not correctly con-
nected 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 digital amplifier is ideally suited for
multi-room PA applications . For this pur-
pose, model PA-1450D is equipped with
four channels, model PA-1850D with eight
channels . Each channel will be able to deliver
an RMS power of 50 W .
4 Setting Up
The amplifier is designed for installation into
a rack (482 mm / 19"); however, it is also suit-
able as a tabletop unit . In order to ensure
sufficient cooling, air must always be able
to flow freely through all air vents .
4.1 Installation into a rack
For installation into a rack, the amplifier
requires a space of 2 RS (RS = rack space
= 44 .45 mm) . To prevent the rack from be-
coming top-heavy, insert the amplifier into
the lower section of the rack . The front plate
alone is not sufficient for fixing it safely; ad-
ditionally use lateral rails or a bottom plate
to secure the unit .
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 (e . g . DPVEN-03) .
5 Connecting the Amplifier
All connections must be made by skilled per-
sonnel only . Always switch off the amplifier
before making any connection!
5.1 Speakers
The speaker terminals can be found under
the protective covers (7) . For connection,
remove the covers .
WARNING Never operate the amplifier
without the covers (7) . During
operation, dangerous high
voltages of up to 100 V are
present at the speaker ter-
minals (8) . After connection,
always replace the covers to
prevent any contact with the
terminals .
Each channel allows connection of either PA
speakers (figs . 9 and 10) or a 4 Ω speaker or
a speaker group with a total impedance of
at least 4 Ω (figs . 5 – 8) .
5.1.1 PA speakers
Caution! For PA speakers (figs . 9 and 10),
the total load by the speakers
must not exceed 50 W RMS for
each channel; otherwise, there
will be overload and the amplifier
may be damaged .
Connect the speakers, in groups for each
channel, to the terminals COM and 100 V or
70 V (8) . Observe the correct polarity (posi-
tive and negative connections as shown in
figs . 9 and 10) . The positive connection of
the speaker cables is always clearly marked .
5.1.2 4 Ω speaker or speaker groups with
a total impedance of 4 Ω
The figures 5 to 8 show various ways to
observe the minimum impedance of 4 Ω .
However, there are other possibilities . Con-
nect the speakers for each channel to the
terminals COM and 4 Ω (8) . Always observe
the correct polarity (positive and negative
connections as shown in figs . 5 – 8) . The
positive connection of the speaker cables is
always clearly marked .
5.2 Inputs
Connect the signal sources (e . g . CD player,
preamplifier, mixer) to the jacks INPUT (5, 6):
— The XLR jacks (5) are designed for bal-
anced signals . For rated output power,
they require an input signal of at least
550 mV .
— Connect signal sources with unbalanced
signals to the RCA jacks (6) . For rated
output power, a signal of at least 1 V is
required .
5.3 Power supply and emergency
power supply
1) Finally, connect the mains cable provided
to the mains jack (10) first, and then con-
nect it to a mains socket (230 V/ 50 Hz) .
2) To ensure continued operation after
power failure, connect a 24 V emergency
power supply unit (e . g . PA-24ESP from
MONACOR) to the terminals 24 V (11) .