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M-Series
M-Series
Be Aware: If the OVER TEMP LED comes on fre-
quently, something is overworking the amplifier or it’s
not properly ventilated. Look at each of the “extreme
conditions” described above and try to determine what
is causing the amplifier to overheat. Refer to “Thermal
Considerations” on page 16 or to the “Troubleshooting”
section in Appendix A for more help.
You may ask, “Why don’t the fans just
go fast all the time?” Well, if it did,
you might actually hear it whirring
during your quiet moments (there
are quiet moments in your life,
aren’t there?). While this whirring
would be of no concern in most live-sound situations, it
could become annoying in a control room environment.
So, when the M-Series amplifier is not working hard, the
fans are off (or they go slow); when the music gets loud
and puts the amp to work, the fans go fast.
6. POWER Switch
To make the amp operate, push the top half of the
POWER switch. It clicks into place and the light in the
switch illuminates. To turn the amp off, push the lower
half. It’ll click again and the light will extinguish.
When you power up the M-Series amplifier, a built-in
delay circuit prevents any pops or thumps from being
transmitted to the speakers due to turn-on instability
in the system. Be sure the signal driving the amplifier is
turned down when you first power up the system. There
are few things as rude as 3 seconds of silence followed
by 250 watts of full-blast stereo sound! (Well, maybe 250
watts of accordian music...)
If you shut down your system, turn off your amplifiers
first. When powering up, turn on your amplifiers last.
This way, equipment feeding the amp won’t “pop” or
“thud” when it’s powered up or down.
Rear Panel
The rear panel of the M-Series amplifiers is comprised
of the fans, the input and output connectors, and a num-
ber of cool extra features.
7. SPEAKER OUTPUTS
There are two methods for connecting your speakers
to the M-Series amplifier, binding posts and Speakon
®
connectors.
To use the binding post outputs, you can terminate
your speaker cables with single or double banana plugs,
spade lugs, or leave them unterminated with bare wire.
Unscrew the amp’s binding posts enough to reveal the
holes on their sides, then insert your stripped wires
(stripped about 3/8" back) into the holes and retighten
the posts (finger tight is fine — please don’t reef on
them with a wrench!). Be careful that no runaway
strands touch the chassis or other terminals.
The red posts are labeled “+,” which means positive.
The black posts are labeled “–” for negative. You prob-
ably know the importance of getting these terms correct
— if one side is hooked up “in phase” and the other side
is “out of phase,” you’ll be “out of work.” (By the way,
although everyone says “phase” in this situation, the cor-
rect word is “polarity”... but it’s not as much fun to say.)
Using high-quality stranded speaker cable (16 gauge
or thicker), connect the positive outputs of the ampli-
fier to the positive inputs of your speakers, and the
negative outputs to the negative inputs. The exception:
If you’re using the amplifier in BRIDGE mode, this does
not apply, (see Bridge Mode on page 19).
In addition to the binding posts, the M-Series ampli-
fier also has Speakon SPEAKER OUTPUTS. These have
the advantage of locking into place, and many profes-
sional loudspeakers are equipped with Speakon connec-
tors. There are three Speakon connectors, for channel 1,
channel 2, and for a bridged connection.
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POWER
H I G H E F F I C I E N C Y P O W E R A M P L I F I E R