MX S
eries P
rofes
sional P
ow
er Amplifiers
12
MX Series Professional Power Amplifiers
9. Power Switch
Press the top of this rocker switch inwards to turn
on the amplifier. Press the bottom of this rocker switch
inwards to turn off the amplifier.
The power LEDs [11] will illuminate when the power
switch is on.
As a general guide, the mixer (or other
signal source) should be turned on first,
followed by the amplifier(s). As such, the
amplifiers should also be turned off first, followed by
the mixer. This will reduce the possibility of any turn-on
or turn-off thumps and other noises generated by any
upstream equipment from coming out of the speakers.
10. Level Controls
These two knobs control the output levels of
channels 1 and 2. The knobs are detented to make
it easy to set both controls to the same level.
Usually, these are set all the way up.
You might turn them down slightly if you have
high-efficiency speakers. Also, you could use
them to control the level of line-level sources such
as a CD player connected directly to the amplifier
without a preamplifier or mixer.
The amplifiers are designed so that a +3.4 dBu
(1.15 Vrms) input signal drives the amplifier to full
power into 4
Ω
:
MX2500 = 750 watts per channel into 4
Ω
MX3500 = 1350 watts per channel into 4
Ω
This equates to a gain of 33 dB and 37 dB
respectively.
After you have set the levels for the mixer
(or other signal source), adjust the level controls
on the amplifier as the final adjustment to set the
overall volume for the system.
In stereo and parallel mode, use both level controls
to control the levels going to each speaker.
In bridged mode, turn the channel 2 level
control down, and just use the channel 1 control.
11. LEDs
From bottom to top, the LED ladder indicates
the following:
PWR –
PWR is short for “power.” These LEDs
illuminate once the amplifier has been powered
on.
SIG –
SIG is short for “signal present.” These
LEDs indicate when a signal is present after
the level controls, at the output stage of the
power amplifier. If the level controls are turned
all the way down (fully counterclockwise),
these indicators will not light.
CLIP –
CLIP is short for “clipping.”
This indicates that the output of the amplifier
has reached its maximum and is clipping.
Clipping is very bad for speakers and should
be avoided to prevent damage.
It is okay if the CLIP LEDs blink
occasionally. It means that the transient
peaks of the music are just hitting
the full output of the amplifier.
However, if the CLIP LEDs are blinking
frequently or continuously, turn down
the source signal (i.e., the mixer’s master
faders) or the amplifier’s level controls.
FAULT –
MX Series amplifiers are equipped
with a thermal protection circuit that monitors
the internal temperature of the heatsink.
If the temperature exceeds a safe operating
level, this indicator lights and the input signal
is muted to allow the amplifier to cool. When
the temperature cools to a safe level once
again, the fault protection circuit deactivates,
the fault LED turns off and the MX amplifier
returns to normal operation.
When the amp is in fault mode, the power LEDs
will remain lit, indicating that the unit is still
powered on despite the lack of output.
Activation of the fault LEDs is an
indication that you should take steps
to avoid continued thermal problems.
See “Thermal Considerations” on
the following page.
MX Series Amplifiers: Front Panel Features
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