Operation; Specifications - Monacor PA-24FR Bedienungsanleitung

2-Channel Anti-Feedback Controller
These operating instructions are intended for
users with basic knowledge in audio technology .
Please read the instructions carefully prior to op-
eration and keep them for later reference . Please
unfold page 3 . Then you will always see the
operating elements and connections described .
1 Overview
1 Switch FREQ SHIFT
BYPASS PA-24FR is bridged; the signal will
not be shifted .
OPERATE The unit will shift the input signal
by the frequency adjusted .
2 LED OSC: will flash at the frequency adjusted
when the switch FREQ SHIFT (1) is in the
position OPERATE
3 Selector switches for the frequency shift:
With all switches in the position OFF, the
frequency will be shifted by 3 Hz;
with several switches in the position ON, the
switch for the highest frequency will define
the value of the frequency shift
4 LED Indicators of the noise gates: will light
up when the corresponding channel is
switched on by an input signal of sufficient
volume
5 Power LED
6 Power switch
7 Mains jack for connection to a socket (230 V/
50 Hz) via the mains cable provided
8 Signal outputs (screw terminals*)
9 Signal outputs (XLR jacks)
10 Signal inputs (screw terminals*)
11 Signal inputs (XLR jacks)
* To facilitate handling, the green screw terminals can
be disconnected from the unit .
2 Safety Notes
This 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 only and do
not insert anything into the
air vents . Inexpert handling or modification
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 ambi-
ent temperature range 0 – 40 °C) .
•
Do not place any vessel filled with liquid on
the unit, e . g . a drinking glass .
•
The heat generated inside the unit must be
dissipated by air circulation; therefore, the air
vents of the housing must not be covered .
•
Do not operate the unit and immediately dis-
connect the mains plug from the socket
1 . if the unit or the mains cable is visibly dam-
aged,
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 for disconnecting
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 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
not repaired in an expert way .
If the unit is to be put out of operation
de finitively, take it to a local recycling
plant for a disposal which is not harm-
ful to the environment .
3 Applications
The anti-feedback controller PA-24FR is specially
designed for PA systems . It is used for preventing
acoustic feedback in speech applications . Such
feedback will occur, for example, when a signal
is picked up by a microphone, amplified and
reproduced by speakers and then picked up by
the microphone again . Due to this loop created,
the signal will be amplified again and again,
resulting in an annoying howling .
The unit will slightly increase the frequency
of the signal to be amplified . As the signal will
be further increased each time is goes through
the feedback loop, feedback howling will largely
be prevented .
All frequencies will be increased by the same
value so that the intervals between the notes
will not be quite correct any more when music
is reproduced . The higher the frequency shift
adjusted, the more noticeable the mistuning
(especially with low notes) . Thus, the suitability
of PA-24FR for music reproduction is limited .
4 Setting Up and Connecting the Unit
PA-24FR is designed for installation into a rack
(482 mm / 19"), however, it can also be used as
a desktop unit to be placed as desired . For in-
stallation into a rack, 1 RS (RS = rack space =
44 .45 mm) is required .
Prior to making or changing any connec-
tions, switch off PA-24FR and the units to be
.
connected . Either use the XLR jacks or the screw
terminals . To facilitate handling, the green screw
terminals can be disconnected from the unit .
1) If the PA system is equipped with a PA mix-
ing amplifier, insert PA-24FR into the mixing
amplifier (fig . 3):
Connect the preamplifier output of the mix-
ing amplifier (possibly marked PRE OUT) to
one of the inputs (10 or 11) of PA-24FR . Con-
nect the corresponding output (8 or 9) of
PA-24FR to the power amplifier input of the
mixing amplifier (possibly marked AMP IN) .
2) If the PA system is equipped with a PA pre-
amplifier and a PA power amplifier, insert
PA-24FR between these two units (fig . 4):
Connect the output / outputs of the preampli-
fier to the input / inputs (10 or 11) of PA-24FR
and the output / outputs (8 or 9) of PA-24FR
to the input / inputs of the power amplifier .
3) Finally connect the mains cable provided, first
to a mains jack (7) and then to a mains socket
(230 V/ 50 Hz) .
Note: If the connection of PA-24FR is unbalanced, the
output level will be lower than the input level .

5 Operation

1) Switch on PA-24FR with the POWER switch
(6) . The yellow power LED (5) will light up .
2) Set the switch FREQ SHIFT (1) to the position
OPERATE .
3) Once a signal at sufficient volume is present
at the input, the corresponding noise gate
will switch the signal shifted in frequency
to the output . The corresponding LED (4)
will light up .
4) Slowly increase the volume of the PA system
until the desired value is reached or feedback
howling starts . In case of feedback howling,
use the switches 4 – 15 Hz (3) to select a fre-
quency which will suppress howling:
Increase the frequency step by step from
3 Hz to 15 Hz . With all switches in the upper
position OFF, the frequency will be shifted by
3 Hz . Set the switches 4 – 15 Hz successively
to ON until howling stops . The switch in the
position ON with the highest frequency will
define the value of the frequency shift .
5) Increase the volume to the value desired . If
howling recurs, modify the frequency again .
6) When reproducing music, set the switch
FREQ SHIFT to the position BYPASS, if pos-
sible .
Note: In case of mains failure or if PA-24FR is switched
off, the bypass function will switch the input signal to
the output without shifting it .

6 Specifications

Inputs
Sensitivity: � � � � � � � � � � � �0�775 V
Impedance� � � � � � � � � � � � �60 kΩ
Connection: � � � � � � � � � � �balanced, XLR jacks and
screw terminals
Outputs
Output level:� � � � � � � � � � �0�775 V
Impedance: � � � � � � � � � � �50 Ω
Connection: � � � � � � � � � � �balanced, XLR jacks and
screw terminals
Frequency range: � � � � � � � � �20 – 20 000 Hz, −1 dB
S / N ratio: � � � � � � � � � � � � � �> 70 dB
THD: � � � � � � � � � � � � � � � � � �< 0�05 %
Frequency shift: � � � � � � � � � �3 – 15 Hz, adjustable in
steps of 1 Hz
Power supply: � � � � � � � � � � �230 V/ 50 Hz
Power consumption: � � � � � �10 VA
Ambient temperature: � � � � �0 – 40 °C
Dimensions (W × H × D): � �482 × 44 × 230 mm,
1 RS (rack space)
Weight: � � � � � � � � � � � � � � � �2�4 kg
Subject to technical modification .
All rights reserved by MONACOR ® INTERNATIONAL GmbH
& Co. KG. No part of this instruction manual may be repro­
duced in any form or by any means for any commercial use.
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