Mackie FRS1700 Owner's manual - Front Panel Features

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FRS Series Amplifiers

FRS Series Amplifiers

OL

-3

-6

-9

-20

SIG

OL

-3

-6

-9

-20

SIG

2

O

O

MAX

MAX

O

O

1

FRS

•

2800

FAST RECOVERY POWER AMPLIFIER

Front Panel Features

1. Power

Use this rocker-style switch to turn the unit on or off. 

This connects / disconnects the AC power to the AC 

power transformer.

 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 Power On LED at the top of the switch will light 

when the power switch is on.

2. Ventilation

Keep these ventilation slots free from any  

obstructions, so the air may flow freely and cool  

down the power transistors.

3. 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.

4. 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    

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 ohms:

FRS•1700 = 540 watts per channel into 4 ohms

FRS•2800 = 850 watts per channel into 4 ohms

This equates to a gain of 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  

control down, and just use the channel 1 control. 

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