Amp Mode Switch; Sensitivity Switch; Fan Vents - Mackie MX Series Owner's Manual

MX Series Amplifiers: Rear Panel Features continued...

6. Amp Mode Switch

This switch determines the input signal routing within
the amplifier. The stereo setting will be used in most
applications. However, some applications might be
better suited for using either the bridge or the parallel
setting.
Stereo: This is the normal position used when
amplifying stereo signals. This mode accepts
separate left and right inputs (1 and 2),
and routes them to the channel 1 and channel 2
outputs. Each channel's level control adjusts
the gain for its own channel, and each channel
is independent.
Bridge: This mode accepts a single input
(Ch. 1), and uses the bridge amplifier output
(Ch. 1) to power one speaker. Use the channel
1 level control to adjust the gain (turn
the channel 2 level control all the way down).
The hookup diagram on page 7 shows how
to connect a speaker in bridged mode.
Parallel: This mode is used when you want
to send a mono signal to both outputs.
It accepts a single input (Ch. 1), and routes
it to both the channel 1 and channel 2 outputs.
Each channel's level control adjusts the gain
for its own channel.
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7. Sensitivity Switch

In a sentence, this switch adjusts the amplifier's
input to match the equipment's output. You should
match it with the output level of whatever is before
the amp in the audio chain. In most cases, it's a mixer's
outputs, but it could also be a preamp, etc.
The switch positions and corresponding dBu level
are listed below:
• 0.775V equals 0 dBu.
• 1.4V equals +4 dBu.

8. Fan Vents

These fans move air over the heatsinks to cool down
the power transistors. If these vents are restricted,
then the amplifier may overheat and shut down.
Do not obstruct the fan ventilation openings
of the amplifier.
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Owner's Manual