ENGLISH
10 - 13 Level controls for input sensitivity
These controls can be used to match the input sensitivi-
ty of the individual channels - A to D - to the output vol-
tage of the connected head unit. These controls are not
volume controls and are solely intended for the purpose
of sensitivity trimming. The control range extends from
700 mV to 8 V.
14 Active low pass filter
This control enables the frequency range of the integra-
ted subwoofer amplifier to be infinitely variable from 50
to 250 Hz low-pass. (see Fig. 1)
15 Level control for the subwoofer amplifier
This control enables the level of the subwoofer to be
adjusted to requirements independently of the other
channels. (see Fig. 2)
16 Subwoofer amplifier input selector
Setting A
The subwoofer amplifier operates with the summation
signal of the 4 inputs with allowance for the input level
of the individual channels. The frequency range is adju-
sted with the aid of low pass filter 14. Additionaly a
mono-summation signal is also available at cinch socket
21 for driving e.g. a centerspeaker-amplifier.
Setting B (only HXA 500 MK II)
Cinch socket 21, is connected as the input of the sub-
woofer amplifier. The signal can be adjusted with the aid
of the integrated active crossover controls (controls 14
and 15).
Setting B (only HXA 500Q MK II)
Cinch socket 21, is connected as the input of the sub-
woofer amplifier. The signal can be adjusted with the aid
of the integrated parametric equalizer (controls 25 to 28)
and with the aid of the active crossover controls (control
14 and 15).
Setting C (only HXA 500 MK II)
Cinch socket 21 is connected as a direct input of the sub-
woofer amplifier. This is expedient if there is a signal
available specially for the subwoofer amplifier, e.g. sup-
plied from an equalizer or head unit.
Setting C (only HXA 500 Q MK II)
Cinch socket 21 is connected with the parametric equa-
lizer of the subwoofer amplifier.
17 - 18 Plug-in frequency crossover modules
The HXA 500 MK II/HXA 500Q MK II are equipped as
standard with an 85 Hz/12 dB Oct. frequency module.
Other plug-in modules compatible with all HELIX
Precision Line amplifiers such as variable high-
pass/low-pass frequency modules, are available on
request. The individual functions of the frequency
modules are visually displayed by colored LEDs.
These have the following meanings for all modules:
yellow
= high pass
green
= full range
red
= low pass
If required the plug-in frequency crossover modules are
available with a 28 Hz/18 dB Oct. subsonic filter. For
additional frequency modules see page 7.
19 Selector switch for channels A and B
For switching the plug-in frequency crossover modules
to high pass, full range or low pass.
20 Selector switch for channels C and D
For switching the plug-in frequency crossover modules
to high pass, full range or low pass.
21 Cinch input and output
The cinch socket is employed, as indicated in the
description relating to Selector 16, either as a fifth input
of the subwoofer amplifier (selector positions B and C)
or as an output (selector position A).
22 Speaker connection terminals for channels
A and B
23 Speaker connection terminals for channels
C and D
24 Speaker connection terminal for the subwoofer
This connection consists of two positive terminals and
two ground terminals in order to allow a
higher cable cross section or to enable two subwoofers
to be connected in parallel. The impedance minimum
of all connected loudspeakers must not be higher than
2 ohms (in bridged mode of the channels AB / CD,
4 ohms). With the use of ported woofer enclosures this
value can be passed very easy. In this case please ask
the manufacturer of the woofer.
Important notice!
Never connect the speaker cables to the vehicle ground
(chassis). This can destroy your amplifier. Ensure that
all the speaker systems are correctly connected, i.e. plus
to plus and minus to minus. The plus pole is indicated on
most speakers.
Parametric equalizer of the HXA 500Q MK II
The HXA 500Q MK II amplifier features a highly inno-
vative integrated parametric equalizer for the subwoofer
amplifier. This means a wide range of possibilities for
individual adaptation of the subwoofer. Besides the
HXA 500Q MK II has an integrated subsonic filter 26
Hz/ 30 dB Oct.
25 Setting the center frequencies
Control 25 can be used to select a frequency of
50 - 150 Hz on the preset low-pass frequency band (see
control 14). This center frequency can be raised using
control 26, by between 0 and 9 dB. This is desirable if
certain frequencies of the subwoofer are to be enhanced
(kick bass) or corrected. (see Fig. 3)
26 Level control for raising the cut-off
frequencies
This control enables the center frequency set at control
25 to be raised from between 0 and 9 dB. (see Fig. 4)
27 Band width adjustment
Control 27 can be used to enhance the Q of the frequency
set at control 25. The resultant band width can be infinitely
varied from 10 to 110 Hz. (see Fig. 5)
The bandwidth remains constant if the centre frequen-
cy (control 25) is changed.
28 Phase Control
This control enables the phase of the bass signal to be
shifted by 180° in order to achieve optimum delay equa-
lization with the other channels.
(see Fig. 6)
Important notice!
Incorrect adjustment of the parametric equalizer can
have a considerable deleterious effect on sound quality.
In such cases, consult your BRAX/HELIX dealer. If this
is not immediately possible, turn controls 25 to 28 com-
pletely counter-clockwise so that the subwoofer ampli-
fier operates in the linear mode.
29 - 31 CPS-Colour Protection System
The LEDs show the operation status of the amplifier.
Green (control 29) = O.K.; yellow (control 30) = the
speakers wires are shorted to ground; red (control 31) =
over heated. If the amp shuts off due to overheating it
will take some time (depending on the outside tempera-
ture) until it switches on again.
32 Bridge selector
To run the satellite channels A+B and C+D in bridged
mode, the control 32 must be setted at position B and
control 9 at position 2. The signal inputs 8+7 and level
controls 10+13 have to be used as input. If the variable
modules HCC 3 - HCC 6 are inserted and the amplifier
is running in bridged mode the controls (HP+LP) which
turn to the output transistors, are in operation.
Important notice:
The impedance in bridged mode must not be lower
than 4 ohms!
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