Front Panel Features; Power; Ventilation; Meters - Mackie FRS-1300 Owner's Manual

Front Panel Features

1. POWER

Use this rocker switch to turn the unit on or off. This
connects/disconnects the AC power to the amplifier's
switching power supply.
The amplifier is on when the top of the switch is
pressed in. It is off when the bottom of the switch is
pressed in.
The LED at the top of the switch will light when the
power switch is on.

. VENTILATION

Keep these ventilation slots free from any obstruc-
tions, so the air may flow freely and cool down the power
transistors.

. METERS

OL is short for "overload." These indicate when the
output of the amplifier has reached the maximum, and
is right on the edge of clipping. Clipping is very bad for
speakers and should be avoided to prevent damage.
It is okay if the OL LEDs blink occasionally. It means
that the transient peaks of the music are just hitting
the full output of the amplifier. However, if the OL LED
is blinking frequently or continuously, turn down the
source signal (i.e., the mixer's master faders) or the
amplifier's level controls.
The meters indicate the signals are below maximum
output power by: –3 dB, –6 dB, –9 dB, and –20 dB.
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.
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•
FRS 2800
FAST RECOVERY POWER AMPLIFIER
1
OL
-3
-6
-9
-20
MAX
O O SIG
8
FRS SERIES AMPLIFIERS
4
2
OL
-3
-6
-9
-20
MAX
SIG O O

. LEVEL CONTROLS

These two knobs control the 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 con-
nected 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 ohms:
FRS•1300 = 420 watts per channel into 4 ohm
FRS•1700 = 540 watts per channel into 4 ohms
FRS•2800 = 850 watts per channel into 4 ohms
This equates to a gain of 32 dB, 33 dB, and 35 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 mono mode, use both level controls to
control the levels going to each speaker.
In bridged mono mode, turn the channel 2 level con-
trol down, and just use the channel 1 control.
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