MACKIE DESIGNS INCORPORATED
16220 Wood-Red Rd. NE
Woodinville • WA • 98072 • USA
Toll-Free 800/258-6883 • FAX 425/487-4337 • E-mail: [email protected]
www.mackie.com
®
1. GENERAL. The amplifier
shall have a free-standing
frame with front and rear
brackets for rack-mounting,
and supplied with four
resilient feet suitable for table-
top placement. The amplifier
shall be capable of two-channel
operation, with a switch to
place the amplifier into single-
channel operation by bridging
the outputs of the two channels.
2. POWER OUTPUT. The
power amplifier, being of two
channels, shall deliver a rated
continuous average sine wave
power output over a 20Hz to
20kHz bandwidth of 250 watts
RMS into 8 ohms per channel,
425 watts into 4 ohms, and
630 watts into 2 ohms with
both channels operating, with
no more than 0.05% total
harmonic distortion. In single-
channel operation it shall
deliver 850 watts RMS into
8 ohms and 1260 watts into
4 ohms, with no more than
0.05% total harmonic
distortion.
The power amplifier shall
deliver a maximum continu-
ous average sine wave power
output over a 20Hz to 20kHz
bandwidth of 300 watts RMS
into 8 ohms per channel, 500
watts into 4 ohms, and 700
watts into 2 ohms with both
channels operating, with no
more than 1% total harmonic
distortion. In single-channel
operation it shall deliver 1000
watts RMS into 8 ohms and
1400 watts into 4 ohms, with
no more than 1% total
harmonic distortion.
3. POWER SUPPLIES. All
necessary operating voltages
for the amplifier shall be
provided by an internal power
supply. A master power switch
shall be located on the front
panel along with a green
power-indicating light.
4. INPUT CHANNEL
CONNECTIONS. Each
monaural input channel
shall have an electronically
balanced line-level input,
presenting no less than a 20k
ohm impedance to the source.
Each input shall have an input
sensitivity of +4dBu, requiring
no more than 1.23V rms to be
driven to rated output into a
4 ohm load. The input
connector shall appear on the
rear panel as a female XLR-3
type connector. In addition,
each monaural input channel
shall have a parallel 1/4" TRS
phone jack and a male XLR-3
type connector, which can be
used as inputs or “thru” jacks
for daisy-chaining the input
signal to another amplifier.
Pin 2 of the XLR connectors,
and the tip of the 1/4" TRS
phone jack, shall be non-
inverting.
5. INPUT CHANNEL LEVEL
CONTROLS. Each monaural
input channel shall be equipped
with a gain control appearing
on the front panel, each
having 40 detent positions,
and calibrated in dB and volts.
6. FRONT PANEL INDICA-
TORS. Each channel shall
have an associated six-segment
LED meter appearing on the
front panel, capable of
displaying signal present,
–20dB, –9dB, –6dB, –3dB,
and overload. Each channel
shall have internal status LEDs
appearing on the front panel
to indicate activation of protect
mode and short-circuit
protection. Two temperature
status LEDs shall appear on
the front panel, one to
indicate normal operation
(COLD) and one to indicate
thermal protection (HOT).
7. PROTECTION FEATURES.
The amplifier shall provide
delayed activation of the
outputs at turn-on. Each
channel shall have a short-
circuit protection circuit for
detecting excessive current
flow at the output that, when
activated, mutes the output
for four seconds. The short-
circuit protection shall
continuously cycle on and off
until the shorted condition is
remedied. The amplifier shall
have a thermal protection
circuit to protect the power
devices from over-temperature
operation. The circuit shall
activate when the internal
temperature crosses the safe-
operating threshold and,
when activated, mute the
outputs until the internal
temperature cools to a safe-
operating temperature, at
which time the amplifier shall
resume normal operation. The
amplifier shall have a fan to
cool the heat-producing
internal components, drawing
cool air in from the front, and
exhuasting warm air out
through both sides. The fan
shall operate at two speeds,
the speed being determined
by the internal temperature
and the signal level present at
the output. The amplifier shall
have an SCR crowbar circuit to
protect the speakers against a
catastrophic amplifier failure.
The circuit shall activate in the
presence of continuous DC at
the speaker outputs, and shall
shut the amplifier down by
turning off the high-voltage
rails.
8. OUTPUT CONNECTIONS.
Each channel shall have a
heavy-duty 5-way binding
post speaker output connec-
tor appearing on the rear
panel, with 3/4" spacing for
accommodating standard
double banana plugs as well
as spade lugs or bare wires.
Each channel shall have a 1/4"
TS phone speaker output jack
appearing on the rear panel in
parallel with the binding post
output.
9. AMP MODES. The
amplifier shall have a three-
way switch appearing on the
rear panel for selecting the
mode of operation, which
shall include stereo (two
channels in, two channels
out), mono (one channel in,
two channels out), and bridge
(one channel in, one channel
out, bridged between both
speaker outputs).
10. OUTPUT APPLICATION.
The amplifier shall have a
three-way switch appearing
on the rear panel for selecting
between limiter on, limiter off,
and subwoofer mode. The
defeatable electronic limiter
circuit shall sense the onset of
clipping and shall limit the
input signal and thereby
prevent the output from
clipping. The amplifier shall
have a two-way switch
appearing on the rear panel
for selecting between a 63Hz
and 125Hz low-pass cutoff
frequency when subwoofer
mode is selected.
11. LOW-CUT FILTER. Each
channel shall have a low-cut
filter with a variable frequency
control appearing on the rear
panel covering a range of
10Hz (OFF) to 170Hz.
12. CONSTANT DIRECTIVITY
HORN EQ. Each channel shall
have a two-way switch
appearing on the rear panel
for selecting a constant
directivity horn equalization
circuit. When selected, this
circuit shall provide a 6dB per
octave high frequency boost.
The EQ shall have a variable
frequency control appearing
on the rear panel covering a
range of 2kHz to 6kHz. The
6kHz position shall be called
AIR.
13. PHYSICAL CONFIGURA-
TION. The amplifier shall be
rack-mountable with rear
support rails for extra support,
and shall have a steel chassis
frame painted grey-black. The
amplifier shall be 19" wide
(483mm), 3.5" (2U) tall
(89mm), and 15.25" deep
(387mm), and shall weigh 36
pounds (16.3kg).
14. DESIGNATION. The
power amplifier shall be a
Mackie Designs M•1400i.
ARCHITECTS AND ENGINEERS SPECIFICATIONS
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