ENGLISH
OPERATION
MANUAL
JB SYSTEMS
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VX - AMPLIFIERS
FRONT PANELS
1. POWER LED:
This blue led is on when you turn the amplifier on using switch(2).
2. MAINS SWITCH:
Used to turn the amplifier on and off. A few seconds after switching
on the amplifier it is ready for operation.
3. GAIN CONTROLS:
These potentiometers are used to control the input sensitivity of
the amplifier. Each channel has its own control.
You can use these controls to set the maximum sound level of your setup:
•
Turn both controls on the amplifier (3) to the left.
•
Put on some music on and make sure the VU meters on your mixer are at 0dB.
(from time to time the red zone is lit)
•
Set the Master output from your mixer to maximum.
•
Open the Gain controls from the amplifier (3) until the maximum desired sound level
is reached.
•
Make sure nobody can reach the Gain controls of the amplifier.
You have just set the maximum level the DJ is able to produce. Your neighbors will be
glad…
☺
(in some cases the DJ is not )
Note for VX200 and VX700:
In Parallel and Bridge mode, only the gain control of the left channel is
used to adjust the input sensitivity.
4. CLIP LED:
Turns on just before the maximum, distortion free, output level of the
amplifier. The clip leds may turn on shortly from time to time but they may certainly not
turn on for longer periods. In this case you have to turn the output level down!
ENGLISH
OPERATION
MANUAL
JB SYSTEMS
4/35
VX - AMPLIFIERS
5. PROTECT LED:
The protection LED is on when the speakers are disconnected from
the amplifier. This occurs in the following situations:
•
During the first seconds after switching on the amplifier.
•
When the temperature of the power stage becomes too high.
•
In case of a technical defect: DC protection!
•
While switching the amplifier off, the “protect led” turns on for a short time.
6. BRIDGE LED:
(only for VX200 and VX700) Indicates that the amplifier is working in
bridge mode. This means that both channels are switched together in series to act as
one mono amplifier. The output power nearly doubles compared to the separate
channels. However the impedance of the connected speaker cabinets must be twice
compared to that of normal stereo mode. In bridge mode, you have to apply the signal
only to the left input of the amplifier. The right input is not used. For more information
refer to point (11) in the next chapter.
Attention:
Take care not to use speaker cabinets with a total impedance lower than 8
Ω
. This will
overload the amplifier!
7. VENTILLATION HOLES:
during its operation the amplifier produces heat that needs
to be dissipated. The fans inside the amplifier must be able to evacuate the heat in the
most effective way. Therefore is it very important not to cover any of the ventilation
openings as this may result in overheating.
8. PARALLEL MODE:
(only for VX200) Indicates that the amplifier is working in parallel
mode. This means that both channels are switched together in parallel to act as one
mono amplifier. The output power nearly doubles compared to the separate channels.
However the impedance of the connected speaker cabinets must be half compared to
that of normal stereo mode. In parallel mode, you have to apply the signal only to the
left input of the amplifier. The right input is not used. For more information refer to
point (11) in the next chapter.
Attention:
to be able to produce the indicated power, the total impedance of the connected speaker
cabinets must be around 2
Ω
!
