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system of the power amp is still functioning correctly
(see 2.2).
2.2.3 Direct Current
If an internal defect causes direct current to be
routed to the output of the VX power amp, it is
diverted from the outputs via a thyristor circuit. This
prevents a dangerous DC signal from reaching t
2.3 Rack Mounting
When mounting VX power amps to 19" transport
racks, be sure to not only fasten the power amps to
the case via the front brackets, but also attach the
rear supporting brackets. Fastening the front
brackets alone may hold the amp in place tempora-
rily, but not permanently. The front rack brackets
cannot bear the weight and stresses alone; you need
the additional stabilization at the back. If you don't,
knocks or vibrations sustained during transport may
lead to power amp chassis damage.
3 Front Panel
3.1 Master Switch
This switch features an integrated automatic circuit
breaker that shuts the power amp off should it be
overloaded. After normal operating conditions are
restored, you don't have to replace any secondary
fuses in the device, simply reactivate the main power
switch. When the amp is powered up, its operational
status is indicated by the green ON LED.
Note: When you are setting up a sound system, the
power amps should be the last devices that you
power up. In other words, don't switch them on until
all other devices are on. When you shut a system
down, always switch off the power amps first and
then all the other devices in the signal chain.
3.2 Ventilation
The internal fan sucks fresh air from the front and
expels the heated air through the vents at the rear of
the amp. If the air intake and/or outlet vents of the
power amp are for some reason obstructed, we
highly recommend that you provide additional venti-
lation. If the flow of air remains unobstructed,
external cooling of the power amp is not necessary.
The intake ventilation duct of the VX power amp is
equipped with a filter that collects dust. We recom-
mend that you clean this filter regularly since a
constant operating temperature significantly increa-
ses the service life of the power amp's electronic
components. To this end, remove the two screws on
the front grille of the VX power amp and then the
grille itself. Next remove the dust filter and rinse it
with warm water. Replacement dust filters are availa-
ble from HK Audio. If you intend to use your power
amp under relatively extreme conditions, it can be an
advantage to remove the filter to maximize the
cooling effect for the power amp. However, if you
remove the filter, the ventilation ducts in the interior
of the power amp must be cleaned regularly by a
qualified service technician.
3.3 Input Level
These control features are used to determine the
amp's input sensitivity. Turning a knob clockwise
increases input sensitivity; i.e. the output signal of
the power amp becomes louder. The dB increments
on the knob indicate by how many decibels the
maximum output of the power amp is reduced.
3.4 Protect LED
This LED can indicate different defects in the
operation of the power amp, depending on how it
illuminates. If the Protect LED goes on and stays on,
the power amp is overheated. Check the connections
and ventilation or provide external ventilation. Once
the power amp has cooled back down to normal
operating temperature, the power amp will
automatically switch itself back on.
If, after cooling back down, the power amp does not
switch back on to normal operating status, this
indicates that there is some type of internal defect.
In this case, a qualified service engineer should
VX_BDA_1_2a 21.08.2003 10:36 Uhr Seite 5 (Schwarz Bogen)
