Operation; Protective Circuit; Specifications - Monacor STA-553D Bedienungsanleitung

5 Connection
Prior to connecting /disconnecting switch off
all units concerned .
5.1 Audio source
The connections of all inputs are balanced .
When connecting audio sources with unbal-
anced output signal, additionally connect the
ground connection "G" to "−" .
5.1.1 Operating mode "2-CH"
1) Engage the switch INPUT MODE (10) .
2) Connect a stereo audio source with line
output level, e . g . mixer, preamplifier, CD
player . Connect the output of the audio
source to the terminals (7): L-CH (left chan-
nel) and R-CH (right channel) .
In this operating mode, the signal for the
low-frequency channel SUB is created from
the stereo input channel .
5.1.2 Operating mode "3-CH"
1) Disengage the switch INPUT MODE (10) .
2) For the high-frequency/mid-frequency
channels, connect a stereo audio source
with line output level, e . g . mixer, pream-
plifier, CD player . Connect the output of
the audio source to the terminals (7): L-CH
(left channel) and R-CH (right channel) .
3) For the low-frequency channel, connect a
mono audio source with line output level
to the terminals SUB, e . g . mono output
of a mixer .
5.2 Speakers
Connect the speakers (minimum impedance:
4 Ω) to the plug-in screw terminals on the
connector panel OUTPUT (11): L-CH = left
channel (mid-range / high-range frequency),
R-CH = right channel (mid-range / high-range
frequency), SUB = subwoofer (low-range fre-
quency) . Make sure that the cable ends are
only stripped for the length required and that
no bare wires protrude (hazard of contact and
short circuit) . When connecting the speakers
make sure that all speakers have the same
polarity .
The power rating of the speakers should
generally not be lower than the output power
☞
of the amplifier ( chapter 8) .
5.2.1 Connecting multiple speakers to
one channel
For the connection of two speakers to one
output, a second row of terminal
screws connected in parallel is
available . When multiple speak-
ers are connected to one chan-
≥8
nel, the total impedance of the
speakers must not fall below 4 Ω
at any channel; otherwise, the
amplifier may be damaged .
≥8
When two speakers of the same impedance
are connected in parallel, the total impedance
will be half the impedance of the individual
speakers . In this case, only speakers with a
minimum impedance of 8 Ω must be used .
5.3 Power supply
For power supply, connect the mains cable
supplied to the mains jack (13) and then to a
socket (230 V~/ 50 Hz) .

6 Operation

Hint: To prevent switching noise, always switch on
the other units of the audio system before switching
on the power amplifier and switch off the power
amplifier before switching off the other units .
1) Before switching on the amplifier for the
first time, set the three volume controls (3)
to zero to make sure that the initial volume
will not be too high .
2) Use the POWER switch (1) to switch the
amplifier on and off . The power LED ON (2)
will light up when the amplifier is switched
on .
3) Adjust the volume controls (3) in such a
way that an ideal balance between the
high-frequency/mid-frequency range and
the low-frequency range is obtained: Con-
trols L-CH / R-CH for the left /right chan-
nels of the high-frequency/mid-frequency
range, control SUB for the low-frequency
range (subwoofer) . If a signal is available,
the LED SIG (5) of the corresponding chan-
nel will light up (depending on the setting
of the volume control) . In case of overload
of a channel, the corresponding red LED
CLIP (6) will light up . Turn back the control
accordingly .
CAUTION Never adjust the amplifier to a
very high volume . Permanent
high volumes may damage
your hearing! Your ear will
get accustomed to high vol-
umes which do not seem to
be that high after some time .
Therefore, do not further in-
crease a high volume after
getting used to it .
6.1 Filter setting
The high pass filters of the two high-frequen-
cy/mid frequency outputs L-CH and R-CH and
the low pass filter of the low-frequency out-
put serve as crossover network .
1) Use the controls 〘 R-CH and 〘 L-CH (8)
to adjust the crossover frequency of the
high pass filters .
2) Use the control 〘 S UB (9) to adjust the
crossover frequency of the low pass filter .
3) If required, use the volume controls (3) to
adjust the balance of the channels .
When adjusting the frequency, take the
frequency range of the connected speakers
into account . Operating a speaker outside its
frequency range may cause distortions and
overload the speaker .
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may be reproduced in any form or by any means for any commercial use.

7 Protective Circuit

The protective circuit is designed to prevent
damage to the speakers and to the amplifier .
When the protective circuit is active, the LED
PROT (4) will light up:
– for a few seconds after the amplifier has
been switched on (switch-on delay)
– when the amplifier is overheated or when
there is a short-circuit at a speaker output
If an LED PROT lights up during operation or if
it fails to extinguish after switch-on, switch off
the amplifier and eliminate the source of error .

8 Specifications

Amplifier class: � � � � � � � � � D
Output power
RMS power CH-1/2: � � � � 2 × 150 W at 4 Ω
RMS power SUB: � � � � � � 250 W at 4 Ω
Peak power: � � � � � � � � � � � 600 W
Input sensitivity: � � � � � � � � 1�5 V
Input impedance: � � � � � � � 14 kΩ
Frequency range: � � � � � � � � 20 – 20 000 Hz
High / low pass filter: � � � � � 50 – 250 Hz,
S / N ratio: � � � � � � � � � � � � � > 96 dB
Channel separation: � � � � � > 70 dB
THD: � � � � � � � � � � � � � � � � � < 0�05 %
Power supply: � � � � � � � � � � 230 V~/ 50 Hz
Power consumption: � � � � � 820 VA max�
Ambient temperature: � � � � 0 – 40 °C
Dimensions (W × H × D): � 482 × 52 × 290 mm,
Weight: � � � � � � � � � � � � � � � 4�5 kg
Subject to technical modification .
® INTERNATIONAL GmbH & Co. KG. No part of this instruction manual
2 × 100 W at 8 Ω
160 W at 8 Ω
12 dB/octave
(1 RS)
7