MA-1212 Mixer Amplifier
120-Watt, 12 Input
Mixer Amplifier
General Description:
The Electro-Voice ® MA-1212 is a 120-watt, twelve-input
mixer amplifier designed for commercial sound
applications. It features twelve separate input controls
which can be used to adjust the level from any of 12 input
sources. Figure 1 shows the layout of the front and rear
Input channels 1-10 are designed to either be used as
low-Z balance microphone or line level inputs. The
combination connector on inputs 1-10 permits use of either
XLR or ¼” input connectors. The block diagram shown in
Figure 2 outlines the signal flow for the MA-1206. A signal
appearing at either input 1 will automatically mute the other
channels unless the mute function is defeated via a switch
on the rear panel.
Inputs 11 and 12 are for auxiliary line-level sources such
as tape or CD players. Mono or stereo signals may be
applied to inputs 11 or 12. The left and right components
of a stereo signal can be applied to the dual RCA phono
jacks of these inputs and mixed together to drive the builtin monaural power amplifier. A rear panel paging input
with gain control is provided for the paging output of a
telephone system. An audio signal appearing at this input
automatically mutes all other inputs. A preamplifier output
jack and power amplifier input jack permit the mixed output
to be fed to an external signal processor (graphic EQ or
compressor), and then returned to the built-in amplifier.
The preamp output may be used to drive an additional
power amp with its own set of speakers without interrupting
the function of the built-in amplifier.
There is also a 24v dc power option to operate the unit off
of a 24v emergency power source. The speaker output is
available at a barrier strip, which includes terminals for
driving low impedance loudspeaker loads, as well as 25,
70.7 or 100 volt distributed systems.
Architects’ and Engineers’ Specifications:
The mixer amplifier shall have twelve input channels, with
individual mix gain controls. Input channels 1 through 10
shall be configured for either low-Z balanced microphone
operation or hi-Z line level signals via switches on the rear
panel. A signal present channel 1 shall trigger the muting
of channels 2-12. The mute circuit shall be defeatable using
a switch on the rear panel. Inputs 1 - 10 shall be available
via combination female XLR / ¼” connectors. Inputs 11
and 12 shall accept either monaural or stereo sources. If
a stereo source is connected, it shall be properly mixed to
mono via a resistor network mounted on the input plate.
There shall be a paging input that accepts a 600-ohm linelevel feed from a phone system. When a signal is present
at the paging input, it shall automatically mute other input
sources. The paging input shall be equipped with its own
gain control. There shall be a master level control. Separate
bass and treble equalization controls shall be provided. The
mixer amplifier shall meet the following performance criteria:
output power shall be 120 watts; total harmonic distortion
shall be less than 1% at 1 kHz; frequency response shall be
within ±3 dB from 50 Hz to 15 kHz; input impedance shall be
600-ohms (balanced inputs) or 47 kW (unbalanced inputs);
nominal load impedance shall be 4-, 8- or 16-ohms for voicecoil-connected loudspeakers, 25, 70.7 or 100-volt nominal
transformer windings for the constant-voltage output.
In addition to a preamplifier output/power amplifier input link,
there shall also be a line-level balanced XLR output. The
mixer amplifier shall operate from either a standard 120 V
ac 50/60 Hz or a 24V dc power source, and measure 13.3
cm (5.2 in.) high x 48.0 cm (18.9 in.) wide x 32.0 cm (12.6
in.) deep. The net weight shall be 11.5 kg (25.4 lb). The
mixer amplifier shall be the Electro-Voice ® Model MA-1212.
Technical Specifications:
Power Output (at 1 kHz): 120 Watts
Frequency Response: 50 Hz - 15 kHz, ±3 dB
Speaker Outputs: 4, 8, 16 ohm, 25, 70.7 and 100-Volt
Tone Controls,
Input Sensitivity/Impedance,
Bass: +-10 dB at 100 Hz
Inputs 1-10 Mic setting: 0.3 mV/600 ohm (balanced)
Treble: +-10 dB at 10 kHz
Inputs 1-10 Line setting: 75 mV/47kohm (balanced)
Muting: 40 dB attenuation
Paging: -20 dBm/600 ohm (transformer
Protection : 3 independent Slo-Blo ® fuses,
primar y ac and dc
Power Amp In: 1 V/10 kohm (unbalanced)
Power Dissipation: 390 watts
Aux: 100 mV to 1V/ (unbalanced)
THD (at rated output): <1% at 1 kHz
Power Supply: 108-132 V ac, 50/60 Hz
Signal-to-Noise Ratio,
Height: 13.3 cm (5.2 in.)
Mic : >52 dB
Width: 48.0 cm (18.9 in.)
Aux: > 65 dB
Depth: 32.0 cm (12.6 in.)
Paging: > 65 dB
Net Weight: 11.5 kg (25.4 lb)
Power Amp In: >90 dB
Shipping Weight: 12.7 kg (27 lb)
Line Output Level/Impedance,
Preamp Output: 1 V/1 kohm (unbalanced)
Balanced Line Output: 500 mV/47 kohm (unbalanced)
Rear View
12000 Portland Avenue South, Burnsville, MN 55337
Phone:952/884-4051, Fax:952/884-0043
© Telex Communications, Inc. 4/2002
Part Number 38110-138 Rev A
U.S.A. and Canada only. For customer orders, contact Customer Service at:
800/392-3497 Fax: 800/955-6831
Europe, Africa, and Middle East only. For customer orders, contact Customer Service at:
+ 49 9421-706 0 Fax: + 49 9421-706 265
Other International locations. For customer orders, contact Customer Service at:
+ 1 952 884-4051 Fax: + 1 952 887-9212
For warranty repair or service information, contact the Service Repair department at:
For technical assistance, contact Technical Support at: 866/78AUDIO
Specifications subject to change without notice.