Connection examples
Connection of the voltage supply ..................Fig. 2, 2a
Connection to car sound system
with cinch output ..........................................Fig. 3
Loudspeaker connections ............................Fig. 4/5
Direct Aux Input.............................................Fig. 6/6a
Remote connection of the amplifi er with
+12V
switchable +12 V voltage source.
This allows the amplifi er to be switched on and off using
the on/off-switch of the radio device.
Note:
If the connection is made using a PnP-INPUT cable,
the switch-on is performed automatically.
!
As a special feature, +12 V/200 mA are now available
as output switching voltage at the remote input/out-
put after automatic switch-on.
High-level connections (via PnP High-
Inputcable only)
The amplifi er features high-level connections (High
Input) to be able to connect to radio devices without
pre-stage outputs (Fig. 2a). This allows for a direct con-
nection at the loudspeaker output of the radio device.
Direct Aux Input connection
Connection option in case of missing or occupied
AUX input at the car sound system
Various NF sources, such as an MP3 player or
a mobile navigation, can be directly connected
via a 3.5-mm jack plug at the Direct Aux Input.
All signal sources can be listened to at the same
time and their volume is adjusted at the respec-
tive source device.
Note:
All NF sources must be switched off during in-
stallation and connection!
Installing the jack plug cable
Please use our 5-m jack plug cable with order
number 7 607 001 525 for the connection.
One of its special features is an on/off switch.
Switch position OFF (•):
For installation and deinstallation and no con-
nected NF source.
Switch setting ON: (I / II):
Only after an NF source has been connected.
Caution:
For the connection, always adjust the volume
control to minimum and switch off the amplifi er.
If you want to listen to one sound source via
the front and rear loudspeakers, you must con-
nect the Direct Aux inputs with our Y jack plug
cable (7 607 001 524), (see Fig. 6).
Level control
The Level control is used to adjust the input sensitivity
of the power amplifi er to the output voltage of your car
sound system.
The adjustment range is from 0.3 V to 8 V.
A few important explanations in this context:
By turning the control clockwise, the input sensitivity of
the amplifi er and, therefore, also the volume increases.
However, this is not a volume control; no further ampli-
fi er output can be achieved in the end position, even if it
may sound like that at the beginning. The system merely
increases the volume faster if the volume control of the
car sound system is turned up.
Loudspeaker connections
(If the amplifi er is to be jumpered, continue with the sec-
tion "Bridged loudspeaker connections" at this point).
As with every audio component, the correct polarisa-
tion of amplifi er and loudspeakers is of essentially
importance for a good bass response. For this reason,
ensure that the positive (+) connection of the amplifi er
is connected with the positive connection (+) of the
loudspeaker; the same applies to the negative (-) con-
nections. In addition, the left amplifi er channel must
be connected with the left loudspeaker and the right
amplifi er channel with the right loudspeaker.
Bridged loudspeaker connections
Note: Not possible for connection via PnP cable.
The THA 555 PnP amplifi er allows for switching the
channels 1+2 and 3+4 as bridge connection. This allows
the amplifi er to be used for one or several subwoofers
or a mid-range driver. In this confi guration, the amplifi er
combines the right and left channel to a single-channel
output (mono output).
Note:
The amplifi er can add the right and left signal informa-
tion only if the right as well as the left RCA connection
were carried out.
Caution:
In a bridge circuit, the amplifi er load must be 4 ohm
or higher. A lower load leads to an overheating or
switch-off of the amplifi er and can cause permanent
damages.
Adjusting the type and range of the frequency
crossovers
With the THA 555 PnP, the type of frequency crossover
(i.e. "Low Pass" or "Hi-Pass") and the desired crossover
frequency can be adjusted. For example, if a pair of
subwoofers is to be connected, low-pass settings are
required. The crossover frequency is dependent upon
the frequency range of the loudspeakers (see recom-
mended frequency range of the loudspeakers).
High-Pass
At a setting of 250 Hz, the amplifi er has a frequency
range of 250 Hz to 30.000 Hz.
THA 555 PnP
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