HELIX P TWO Bedienungsanleitung Seite 19

your speakers. We strongly recommend to only
use volume controlled audio sources!
Information: The P TWO can only handle un-
compressed digital stereo signals in PCM for-
mat with a sample rate between 28 kHz and
96 kHz and no MP3- or Dolby-coded signals.
4. Configuration of the digital signal input (op-
tionally)
If a digital signal source is used you have the
possibility to route the digital signal directly and
loss-free from the integrated DA converter to
the internal power amplifiers. To activate the
direct signal routing you have to change the po-
sition of the SPDIF Direct In switch to "On" (see
page 17, item SPDIF Direct In switch) as well as
the position of the X-Over switch to "Full" (see
page 15, item 7; X-Over).
Note: The switch only affects the signal routing
of the Optical Input.
5. Adjustment of the input sensitivity
Attention: It is mandatory to properly adapt
the input sensitivity of the P TWO to the sig-
nal source in order to avoid damage to the
amplifier.
If you want to change the input sensitivity use
the control 4 (see page 15, item 4; Gain). The
setting of the control affects the lowlevel (Line
Input) and highlevel speaker inputs (Highlevel
Input) as well as the digital signal input (Optical
Input)!
Follow the subsequent steps if you like to per-
fectly adapt the amplifiers input sensitivity to
your audio source by using the control:
1. Don't connect any loudspeakers to the out-
puts of the P TWO during this setup.
2. Turn on the amplifier.
3. Adjust the volume of your head unit / car ra-
dio / digital signal source to approx. 90 % of
the max. volume and playback an 1 kHz full
scale test tone (0 dB).
4. If the Clipping LED already lights up, you
have to reduce the input sensitivity via con-
trol (page 15, item 4; Gain) until the LED
turns off.
5. Increase the input sensitivity by turning the
control clockwise until the LED lights up. Now
turn the control counterclockwise until the
Clipping LED turns off again.
If the Highlevel Input is used in combination
with a standard car radio we recommend an in-
put sensitivity of roughly 9 Volts. For this pur-
pose, turn the control from max. CCW position
to 9 o'clock position.
6. Connection to power supply
Make sure to disconnect the battery before
installing the HELIX P TWO!
Connect the +12 V power cable to the positive
terminal of the battery. The positive wire from
the battery to the amplifier power terminals
needs to have an inline fuse at a distance of
less than 12 inches (30 cm) from the battery.
The value of the fuse is calculated from the
maximum total current draw of the whole car
audio system (P TWO = max. 90 A RMS at
12 V power supply). If your power wires are
short (less than 1 m / 40") then a wire gauge of
16 mm² / AWG 6 will be sufficient. In all other
cases we strongly recommend gauges of 25 -
35 mm² / AWG 4 – 2!
The ground cable (same gauge as the +12 V
wire) should be connected to a common ground
reference point (this is located where the neg-
ative terminal of the battery is grounded to the
metal body of the vehicle), or to a prepared met-
al location on the vehicle chassis, i.e. an area
which has been cleaned of all paint residues.
7. Connecting the remote input
The remote input (REM) has to be connected to
the radio remote output if the amplifiers digital
input or lowlevel line inputs is/are used as sig-
nal input/s. We do not recommend controlling
the remote input via the ignition switch to avoid
pop noise during turn on/off.
If the Highlevel Input is used this input does not
need to be connected as long as the car radio
has BTL output stages.
8. Configuration of the remote input
The P TWO will be turned on automatically if
the highlevel inputs are used or if a signal is
applied to the remote input terminal. The Auto
Remote switch (see page 17, item 18; Auto Re-
mote) allows to deactivate the automatic turn-
on feature. The feature should be deactivated if
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