Owner
’s Manual
15
Owner’s Manual
MX Series Amplifiers Service Information Continued...
Noise / Hum
• Check the signal cable between the mixer and
the amplifier. Make sure all connections are good
and sound.
• Make sure none of the signal cables are routed near
AC cables, power transformers, or other EMI-inducing
devices.
• Is there a light dimmer or other SCR-based
device on the same AC circuit as the amplifier?
Use an AC line filter, or plug the amplifier into
a different AC circuit.
• If possible, listen to the signal source with
headphones plugged into the console.
If it sounds noisy there, the problem is not
in the amplifier.
• Is there a cable-TV audio feed in your system?
An incorrect ground may cause a “ground loop” hum.
• Sometimes it helps to plug all the audio equipment
into the same AC circuit so they share a common
ground.
One side is louder than the other
• Are both level controls set to the same position?
• Check your source signal to make sure the left
and right signals are balanced.
• Are the speaker impedances matched? Different
speaker loads can cause different volume levels
on each side.
• Try switching sides: Turn off the amp, swap
the speaker cables at the amp and turn the amp
back on. If the same side is still louder, the problem
is with your speaker cabling or the loudspeakers.
If the other side is louder now, the problem is with
the mixer, the loudspeaker processor, the amp,
or the line-level cabling.
As the music gets loud, the amp shuts down
• Make sure the OL LEDs are not lighting continuously.
If so, turn down the signal source or the amp level
controls.
• Can the amp breathe? It needs plenty of fresh air
to stay cool. Do not block the ventilation holes.
Other Issues
• Please email or call Technical Support if you
are having any other issue not listed here:
o mackie.com/support-contact
o 1-800-898-3211
Repair
For warranty service, refer to the warranty information
on page 19.
Non-warranty service is available at a factory-authorized
service center. To locate the nearest service center, visit
www.mackie.com/support/service-locator. Service
for MX Series amplifiers living outside the United States
may be obtained through local dealers or distributors.
If you do not have access to our website, please call
our Tech Support department at 1-800-898-3211 (normal
business hours, Pacific Time), to explain the problem.
They will tell you where the nearest factory-authorized
service center is located in your area.
