Installation - HELIX C ONE Manual

Initial start-up and functions
Caution: To avoid a loss of gain make sure that the
crossover frequencies of the high- and lowpass fil-
ters do have an interval of at least two octaves
when generating a bandpass.
That means if the lowpass signal is adjusted to
320 Hz the highpass should be adjusted to 80 Hz
or less (one octave = doubled frequency or halved
frequency). If a subwoofer is connected we recom-
mend to use the highpass control (control 11 / HPF)
as variable subsonic / low-frequency highpass filter
or turn it counterclockwise to 15 Hz to get a sub-
sonic filter.

Installation

Connection of HELIX C ONE to the head unit /
car radio:
Caution: Carrying out the following steps will re-
quire special tools and technical knowledge. In or-
der to avoid connection mistakes and / or damage,
ask your dealer for assistance if you have any ques-
tions and follow all instructions in this manual (see
page 16). It is recommended that this unit will be
installed by an authorized HELIX dealer.
1. Connecting the lowlevel line inputs
Use the correct cable (RCA / Cinch cable) to
connect these inputs to the lowlevel line outputs
of your head unit / car radio. It is not mandato-
ry to use both lowlevel line inputs. If only one
channel will be connected use channel A and
set the Input Mode switch to "MONO".
When both channels will be used please choose
switch position "STEREO" (see page 21,
item 17; Input Mode switch).
2. Connecting a digital signal source
If you have installed the HELIX Digital Input
22
HDM slot
24
The HDM slot is used to mount the optionally avail-
able HELIX Digital Input Module HDM 1.
The module extends the amplifier with an optical
digital input in SPDIF format including SPDIF Direct
In switch.
Thanks to the SPDIF Direct In switch the input stag-
es of the C ONE can be bypassed and allows to
directly route the signals of the digital input from the
integrated DA converter to the internal power stage.
Further information about the module can be found
on page 27.
Module HDM 1 and have a signal source with
an optical digital output you can connect it di-
rectly to the amplifier using the appropriate in-
put.
Important: The signal of a digital audio source
normally does not contain any information
about the volume level. Keep in mind that this
will lead to full level on the outputs of the HELIX
C ONE. This may cause severe damage to your
speakers. We strongly recommend to only use
volume controlled audio sources!
Information: The C ONE 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.
3. Configuration of the digital signal input
If you have installed the HELIX Digital Input
Module HDM 1 and connected a digital signal
source you have the possibility to route the dig-
ital signal directly and loss-free from the inte-
grated DA converter to the internal power am-
plifier. To activate the direct signal routing you
have to change the position of the SPDIF Direct