HELIX DSP PRO MK2 Manual page 17

Initial start-up and functions
1 Line Input
8-channel pre-amplifier input to connect signal
sourc es such as radios. Input sensitivity is
factory-set set to 4 Volts. It is possible to vary the
sensitivity of each channel between 2 and 4 Volts.
inside the device.
2 Coax Input
Coaxial input in SPDIF format for connecting sour-
c es with a digital audio output. The sampling rate of
this input has to be in the range of 12 and 192 kHz.
The input signal is automatically adapted to the in-
ternal sample rate.
In order to activate this input and to control its vol-
ume, we recommend to use an optional remote
control.
Notice: This signal processor can only handle ste-
reo input signals and no Dolby-coded digital audio
stream.
Important: Before first use, the Coax Input has to
be activated in the DSP PC-Tool software or with
an optional remote control. The Optical Input is
activated ex works.
3 Optical Input
Optical input in SPDIF format for connecting signal
sources with a digital audio output. The sampling
rate of this input must be between 12 and 96 kHz.
The input signal is automatically adapted to the
internal sample rate. In order to activate this input
and to control its volume, we recommend to use an
optional remote control.
Notice: This signal processor can only handle ste-
reo input signals and no Dolby-coded digital audio
stream.
Notice: In standard configuration the HELIX
DSP PRO MK2 automatically activates this input if
a digital audio signal is detected.
4 Clipping LED
This LED lights up red if one of the eight Line Inputs
or Highlevel Inputs is overdriven. The LED has no
function if the device is fed with digital input signals.
If this LED lights up reduce the input sensitivity by
using the internal trim potentiometers until the LED
goes out (item 3 page 20; "Adjustment of the input
sensitivity").
5 Highlevel Input
8-channel highlevel loudspeaker input to connect
the signal processor directly to loudspeaker outputs
of OEM / aftermarket radios or OEM amplifiers that
do not have any pre-amplifier outputs. Input sensi-
tivity is factory-set to 10 Volts for all channels.
It is possible to vary the sensitivity of each channel
between 5 - 10 Volts and 10 - 20 Volts inside the
device (item 3 page 20; "Adjustment of the input
sensitivity").
By changing the sensitivity range, the input imped-
ance of the highlevel inputs is shifted as well in or-
der to guarantee a perfect operation in combination
with OE radios and high-power OE amplifiers.
Attention: Solely use the pluggable screw-terminal
for the highlevel connector which is included in de-
livery or an optional available cable harness from
the HELIX accessory assortment!
Important: It is strictly forbidden to use the High­
level Input and pre-amplifier inputs (Line Input) at
the same time. This may cause severe damage to
the pre-amplifier outputs of your car radio.
6 Power Input
This input is used for connecting the signal pro-
cessor to the power supply of the vehicle and for
remote in / out. If the highlevel loudspeaker inputs
are used the remote input can be left unconnected.
The remote output is used for turning on/off ampli-
fiers that are connected to the Line Outputs of the
HELIX DSP PRO MK2. Connect this remote out-
put to the remote inputs of your amplifier/s. This
is essential to avoid any interfering signals. The
remote output is activated automatically as soon
as the booting process of the DSP is completed.
Additionally this output will be turned off during the
"Power Save Mode" or a software update process.
Attention: Solely use the pluggable screw-terminal
which is included in delivery!
Important: Never use a different signal than the
remote output of the DSP to activate connected
amplifiers!
7 Ground lift switch
The ground of the HELIX DSP PRO MK2 signal in-
puts is galvanically decoupled from the ground of
the signal outputs. In many cars this setup is the
best way to avoid alternator noise.
Nevertheless, there are use cases where it will
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