Audio Source; Bridge Mode; Power Supply; Protective Circuit - IMG STAGELINE STA-300D Mode D'emploi

5 Connection
Prior to connecting /disconnecting switch off
all units concerned .

5.1 Audio source

It is possible to connect a stereo audio source
with line level, e . g . mixer, preamplifier, CD
player . Connect the output of the audio
source to one of the two pairs of jacks on
the connector panel INPUT, either to the XLR
jacks (8) or to the 6 .3 mm jacks (9): LEFT = left
channel, RIGHT = right channel .
The 6 .3 mm jacks and the XLR jacks are
balanced . Audio sources with unbalanced
output signal can be connected via 2­pole
6 .3 mm plugs .
The contacts of the XLR and 6 .3 mm jacks
of the same channel are connected to each
other; thus, the jack not used as an input is
available for routing the signal to another
amplifier, for example .
5.2 Speakers
On the connector panel OUTPUT, both 6 .3 mm
jacks (11) and Speakon­compatible speaker
jacks (12) are available for speaker connec­
tion . The 6 .3 mm jacks and the speaker jacks
are connected in parallel . Connect the two
speakers (minimum impedance: 4 Ω) either
to the 6 .3 mm jacks or to the speaker jacks:
LEFT = left channel, RIGHT = right channel .
The switch MODE (7) must be disengaged for
the 2­channel mode .
Insert a Speakon­compatible speaker plug
into the jack and turn the plug clockwise until
it engages . To remove the plug, pull back the
safety latch on the plug and turn the plug
counter­clockwise . At the contacts 2+/ 2−,
the speaker jack LEFT additionally carries the
signal of the right output . This is, for exam­
ple, useful for connecting speaker systems
with separately powered frequency paths (bi­
amping) and for connecting a speaker in the

bridge mode (

☞ chapter 5 .2 .1) .
The power rating of the speakers should
generally not be lower than the output power
of the amplifier ( ☞ chapter 8) .
5.2.1 Bridge mode
The bridge mode is designed to obtain more
power at a speaker . In the bridge mode, the
two amplifier channels are combined to a
mono amplifier: Engage the button MODE
(7) to activate the bridge mode BRIDGE . The
input signal at the left channel will now be
inverted and sent to the right channel . Thus,
the voltage at the output will be doubled
when the speaker has been connected for
the bridge mode as described below . Signals
at the right input will be ignored .
Connection to the output jack LEFT (12) via
a 4­pole Speakon plug:
1+
L+
R+
2+
In the bridge mode, the minimum impedance
of the speaker must be 8 Ω .
5.2.2 Connecting multiple speakers to
one channel
When, in the 2­channel mode, multiple
speakers are connected to one
channel, the total impedance of
the speakers must not fall below
4 Ω at any channel; otherwise,
≥8
the amplifier may be damaged .
When two speakers of the same
impedance are connected in par­
allel, the total impedance will be
≥8
half the impedance of the indi­
vidual speakers . In this case, only speakers
with a minimum impedance of 8 Ω must be
used .
When, in the bridge mode, two speakers of
the same impedance are connected in paral­
lel, the minimum impedance of the individual
speakers must be 16 Ω .

5.3 Power supply

For power supply, connect the mains cable
supplied to the mains jack (14) 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 two volume controls (2)
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 (4)
will light up when the amplifier is switched
on .
3) Use the volume controls (2) to adjust the
volume: Control L­CH for the left channel;
control R­CH for the right channel . In the
bridge mode, only use the control L­CH .
If a signal is available, the LED SIGNAL (3)
of the corresponding channel 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 amplifi­
4) If required, engage the switch LIMITER (10)
to activate the automatic level limiter . This
will reduce distortions at high volumes that
might damage the speakers .
≥8
All rights reserved by MONACOR
may be reproduced in any form or by any means for any commercial use.
er to a very high volume .
Permanent high volumes
may damage your hear­
ing! Your ear will get ac­
customed 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 .
® INTERNATIONAL GmbH & Co. KG. No part of this instruction manual

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 (5) will light up:
– for a few seconds after the amplifier has
been switched on (switch­on delay)
– when the amplifier is overheated or when
there is a short­circuit at a speaker output
If the LED PROT lights up during operation or
if it fails to extinguish after switch­on, switch
off the amplifier and eliminate the source of
error .
8 Specifications
Model STA-300D
Output power
RMS power
stereo mode at 4 Ω 2 × 150 W
stereo mode at 8 Ω 2 × 100 W
bridge mode at 8 Ω 300 W
Peak power 350 W
Amplifier class
Input sensitivity
Input impedance
Frequency range 20 – 20 000 Hz
S / N ratio
Channel separation
THD
Power supply 230 V~/ 50 Hz
Power consumption 550 VA
Ambient temperature
Dimensions (W × H × D) 482 × 52 × 290 mm (1 RS)
Weight 3.7 kg
Subject to technical modification .
STA-500D
2 × 250 W
2 × 150 W
500 W
600 W
D
1 V
12 kΩ
> 96 dB
> 70 dB
< 0.05 %
850 VA
0 – 40 °C
4.7 kg
7