Mackie FR Series M-1200, Service Manual

Page: 7 / 38

VERSION 1.1
SYSTEM OVERVIEW
5
REAR PANEL
1. SPEAKER OUTPUTS
The M•1400 has Speakon

connectors where the M•1200 has ¼” speaker outputs. Both
models have binding posts. For bridged mono operation, the + output comes from
channel one’s positive terminal and - from channel two’s positive.
2. INPUT
The M•1200/M•1400 has both XLR and ¼” TRS inputs. They are electrically identical
(wired in parallel). In bridged mono or parallel mono mode channel 2 input is disabled.
3. THROUGH
Yet another jack wired in parallel with the Inputs, the through jack provides a
convenient way to chain amplifiers or pass the signal to any other device.
4. LOW CUT FILTER
Sweeps the built in high pass filter from 10Hz to 170Hz.
5. CONSTANT DIRECTIVITY HORN EQ/AIR EQ
Built in shelving EQ provides high frequency compensation when using constant
directivity horns.
6. AMP MODE
Three position slide switch selects STEREO, PARALLEL MONO or BRIDGE MONO operation.
Channel One’s input signal is used for PARALLEL MONO and BRIDGE MONO operation.
AMP MODE and OUTPUT APPLICATION switches should not be changed while the unit is
on.
7. OUTPUT APPLICATION
Placing the three position slide switch in its center position defeats the built in LIMITER for
both channels. Selecting SUB WOOFER engages the built in low pass filter. The
FREQUENCY switch selects between 125Hz and 63Hz cutoff for the low pass filter. In SUB
WOOFER mode, inputs 1 and 2 are summed regardless of AMP MODE setting.
(Remember, human hearing is unable to discern direction at frequencies where the
wavelenth is greater than the distance between your ears, ~250Hz unless you have a
grossly large head!)
CHANNEL
2 1
CHANNEL
CH
1
CH
2
SPEAKER OUTPUTS
+
- -
+
63Hz
125Hz
CONSTANT DIRECTIV ITY
HORN EQ/AIR EQ
CONSTANT DIRECTIV ITY
HORN EQ /AIR EQ
INPUT
THRU THRU
INPUT
AMP MODE
FREQUENCY
4.5 kHz
O N
6k Hz 2k Hz
MONO BRIDGE
LIMITER (CH1 & CH2)
OFF
FULL
RANGE
SUB
WOOFER
LOW CUT
FILTER
LOW CUT
FILTER
OUTPUT APPLICATION
CAUTION
BALANCED
O
R
UNBALANCED
BALANCED
O
R
UNBALANCED
AIR EQ
MONO
BRIDGE
ON
/ BRIDGE / MONO
170 Hz OFF
4.5k Hz
6k Hz 2k Hz
AIR EQ
120 VAC 50/60 Hz
1500 WATTS
+
-
170 Hz
100 Hz
OFF
STAGE
MONITOR
100 Hz
STAGE
MONITOR
OFF
TYPICAL
ON
OFF
TYPICAL
TYPICAL
35 Hz
TYPICAL 35 Hz
(MONO BRIDGE)
1200 W A TTS
4 OHM LOAD MIN.
600 W A TTS CH
2 OHMS LO AD MIN.
STEREO
TYPICAL
STEREO
TYPICAL
AIR EQ AIR EQ
1 5
4 6 2
3 7
2
5 3
4