6.2.3 Connecting the second
power amplifier (fig. 4)
To realize e. g. a 2-way active system with mid-
high range speakers and bass speakers or a
subwoofer, a second power amplifier is required.
Connect its inputs in parallel to the inputs of the
first power amplifier via two Y cables (e. g. CBA-
25 / SW from CARPOWER) to the outputs of the
signal source.
6.3 Speakers
It is possible to connect full range speakers
(2-way or 3-way speakers), mid-high range
speakers, bass speakers, or subwoofers. In
2-channel operation, the power amplifier can
drive the speakers for the left channel and right
channel. In bridge operation it can drive the
speaker / s for one channel or a subwoofer with a
higher output power.
Important!
All speakers must be connected with 2 poles,
i. e. without common ground connection.
When choosing suitable speakers, pay in any
case attention to their mechanical and electrical
capability in connection with the power used of
the power amplifier (
chapter 9, specifica-
tions).
Connect the speakers to the
jack SPEAKER (5) via the sup-
plied connection cable. The
connection depends on the
desired operating mode of the
power amplifier:
6.3.1 2-channel operation (fig. 2)
The highest output power is reached when con-
necting 2 Ω speakers or a speaker group with a
total impedance of 2 Ω per channel (e. g. two 4 Ω
speakers connected in parallel). However, it is
also possible to connect individual 4 Ω speakers
in which case the output power is slightly
reduced. Connection:
SPEAKER L ⊕ = positive pole left speaker
SPEAKER L ⊖ = negative pole left speaker
SPEAKER R ⊕ = positive pole right speaker
SPEAKER R ⊖ = negative pole right speaker
6.3.2 Bridge operation (fig. 3)
Attention!
For bridge operation the impedance of the
speaker or the total impedance of speaker
groups must not fall below 4 Ω!
While connecting, pay attention to the lettering
BRIDGED.
SPEAKER L ⊕ positive pole
SPEAKER L ⊖ = remains unconnected
SPEAKER R ⊕ = remains unconnected
SPEAKER R ⊖ = negative pole
7 Setting into Operation
Important!
Prior to the first switching-on, select the filter
with the switch X-OVER (1) and coarsely adjust
the crossover frequency with the control
X-OVER (2) [chapter 7.1] so that the speakers
will not be overloaded by a frequency range
that might be too wide. It is also recommended
to check the entire wiring of the power amplifier
once again for correctness before reconnecting
the negative terminal of the car battery.
7.1 Selecting the filter and adjusting
the crossover frequencies
Depending on the speaker type connected,
select the filter with the switch X-OVER (1).
For full range speakers set the switch X-OVER
to the position FULL. The channels reproduce
the entire frequency range. The control X-OVER
has no function.
For mid-high range speakers set the switch
X-OVER to the position HPF. The high pass is
switched on in the channels and the low fre-
quencies are thus suppressed. For the time
being, coarsely adjust the crossover frequency
with the control X-OVER.*
For bass speakers or subwoofers set the
switch X-OVER to position LPF. The low pass is
switched on in the channels and the medium and
high frequencies are suppressed. For the time
being, coarsely adjust the crossover frequency
with the control X-OVER.*
7.2 Adjusting the level
Hint To keep the interference by the electric
system of the car as low as possible, the
output level of the signal source should be
1.5 V as a minimum.
1) First for basic adjustment, turn the control
GAIN (3) to the left stop to position MIN.
2) Switch on the car HiFi system completely.
The power LED (7) shortly shows red, then
green. If it does not light up or only shows red,
see chapter 8.
3) Adjust the signal source, e. g. the car radio, to
the maximum, non-distorting volume.
4) Turn up the control GAIN so far to the maxi-
mum that no distortions occur.
5) If further power amplifiers are used in the car
HiFi system, attenuate in each case the lev-
els of the channels which are too high to
match the volumes of all channels with each
other.
8 Trouble Shooting
If there is no sound after switching on the car
HiFi system, locate the fault more precisely by
means of the LED (7).
The LED does not light up
1) Check the fuse (8) of the car HiFi amplifier
(30 A) and the additional fuse at the car bat-
tery. Replace defective fuses. Only use fuses
with the indicated values. Do not insert a
higher value in any case. The power amplifier
may be damaged and the guarantee will
expire.
2) Check the 12 V power supply cable and the
ground cable for correct connection and for
interruption.
3) Check at the terminal REM (10) of the power
amplifier if +12 V is present. If not, remove the
cable at the terminal REM and temporarily
short-circuit the terminals REM and BATT (9).
If the power amplifier switches on now, the
fault is due to the missing control voltage.
Check the 12 V control output of the car radio
and the corresponding connection cable to
the power amplifier.
* For a guidance, observe the frequency range of the
speakers used. The fine adjustment is made with cor-
responding meters after the level adjustment.
The LED shows green
1) Check the audio cables from the signal
source to the car HiFi power amplifier. Are
the plugs correctly connected? Are the
cables interrupted?
2) Check the signal source. Is the signal source
switched on? Have the correct outputs been
used? Is the signal source defective?
3) Check the speaker cables for interruption.
4) Check the connected speakers.
The LED shows red
The power amplifier is protected with a protec-
tive circuit against overheating and against short
circuit at the speaker outputs. The protective cir-
cuit also responds when a DC voltage arrives at
the speaker outputs in case of a defect of the
power amplifier and shortly for muting when
switching-on. If the protective circuit is activated,
the LED (7) shows red and the speaker outputs
are switched off.
If the LED does not change from red to
green after switching on the power amplifier or if
it changes to red during operation, switch off the
car HiFi system and eliminate the error. After
eliminating the error or after cooling-down, the
power amplifier switches on again automatically.
9 Specifications
Output power
Max. power: . . . . . . . . . 250 W
RMS power at 2 Ω: . . . . 2 × 70 W
RMS power at 4 Ω: . . . . 2 × 40 W
RMS power in case of
bridge operation at 4 Ω: 140 W
Frequency range: . . . . . . 20 – 30 000 Hz
Min. speaker impedance
2-channel operation: . . 2 Ω
Bridge operation: . . . . . 4 Ω
Input sensitivity
Line (RCA jacks): . . . . . 0.15 – 2.6 V
High Input: . . . . . . . . . . 4 – 7 V
Filters (limit frequencies)
Low passes: . . . . . . . . . 50 – 500 Hz,
12 dB / octave
High passes: . . . . . . . . 50 – 500 Hz,
12 dB / octave
Channel separation: . . . . 55 dB
S/N ratio: . . . . . . . . . . . . . 97 dB (A weighted)
THD: . . . . . . . . . . . . . . . . < 0.07 %
Power supply: . . . . . . . . . 11 – 16 V / 30 A
Ambient temperature: . . . 0 – 40 °C
Dimensions: . . . . . . . . . . . 158 × 44 × 142 mm
Weight: . . . . . . . . . . . . . . 1.15 kg
Subject to technical modification.
All rights reserved by MONACOR
TIONAL GmbH & Co. KG. No part of this instruc-
tion manual may be reproduced in any form or by
any means for any commercial use.
GB
®
INTERNA-
7