O F 8 P A G E S
M•1400/M•1400i
High-Current Power Amplifier
O F 8 P A G E S
M•1400/M•1400i
High-Current Power Amplifier
O F 8 P A G E S
M•1400/M•1400i
High-Current Power Amplifier
M•1400/M•1400i
High-Current Power Amplifer
O F 8 P A G E S
6
(continued on page 7)
Architects’ and Engineers’ Specifications
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 two-channel power ampli-
fier 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 dis-
tortion. 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 at mid-band 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 distor-
tion. 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 volt-
ages 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 imped-
ance to the source. Each input shall have an input sensi-
tivity of +4 dBu, 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 mon-
aural input channel shall be equipped with a gain control
appearing on the front panel, each having 20
detent
positions, and calibrated in dB and volts.
6. FRONT PANEL INDICATORS.
Each channel shall
have an associated six-segment LED meter appearing on
the front panel, capable of displaying signal present,
–20 dB, –9 dB, –6 dB, –3 dB, and overload. Each chan-
nel shall have internal status LEDs appearing on the front
panel to indicate activation of protect mode and short-cir-
cuit 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 pro-
vide 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 out-
puts until the internal temperature cools to a safe-operat-
ing temperature, at which time 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 exhausting 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.
M•1400i: Each channel
shall have a heavy-duty 5-way binding post speaker out-
put connector 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.
M•1400: Each channel shall have a heavy-duty 5-way
binding post speaker output connector appearing on the
rear panel, with 3/4" spacing for accommodating stan-
dard double banana plugs (120V versions only) as well
as spade lugs or bare wires. Each channel shall have a
Neutrik brand Speakon
®
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 chan-
nels out), and bridge (one channel in, one channel out,
bridged between both speaker outputs).
10. OUTPUT APPLICATIONS.
The amplifier shall
have a three-way switch appearing on the rear panel for
