Electro-Voice MA-1212 Mixer Amplifier
MA-1212 Mixer Amplifier
120-Watt, 12 Input Mixer Amplifier
Power Output (at 1 kHz): 120 Watts
Frequency Response: 50 Hz - 15 kHz, ±3 dB
Inputs 1-10 Mic setting: 0.3 mV/600 ohm (balanced)
Inputs 1-10 Line setting: 75 mV/47kohm (balanced)
Paging: -20 dBm/600 ohm (transformer isolated)
Power Amp In: 1 V/10 kohm (unbalanced)
Aux: 100 mV to 1V/ (unbalanced)
THD (at rated output): <1% at 1 kHz
Mic : >52 dB
Aux: > 65 dB
Paging: > 65 dB
Power Amp In: >90 dB
Line Output Level/Impedance,
Preamp Output: 1 V/1 kohm (unbalanced)
Balanced Line Output: 500 mV/47 kohm (unbalanced)
Speaker Outputs: 4, 8, 16 ohm, 25, 70.7 and 100-Volt
Bass: +-10 dB at 100 Hz
Treble: +-10 dB at 10 kHz
Muting: 40 dB attenuation
Protection : 3 independent Slo-Blo ® fuses, primary ac and dc
Power Dissipation: 390 watts
Power Supply: 108-132 V ac, 50/60 Hz
Height: 13.3 cm (5.2 in.)
Width: 48.0 cm (18.9 in.)
Depth: 32.0 cm (12.6 in.)
Net Weight: 11.5 kg (25.4 lb)
Shipping Weight: 12.7 kg (27 lb)
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 panels.
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 1⁄4” 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 built- in 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 / 1⁄4” 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 line- level 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 voice- coil-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.