Extron electronic Front Panel Features, Setting Up the MPA 122 Amplifier, Remote control

Installation and operation, cont’d

4Balanced or unbalanced audio input connector — Marked “L” and “R”, this 3.5 mm captive screw input is for bare wire, balanced or unbalanced audio signals.

Figure 2-7 — 3.5 mm captive screw audio input connector wiring

Remote control

5Remote input connector — An optional 3-pin captive screw connector that allows a wall mounted audio controller or MediaLink product to remotely control volume and mute levels for the MPA 122 unit.

For more information on using the remote input connector, see Chapter 3, Remote Operation.

Audio output

6Speaker connector — Marked “L” and “R”, this 4-pin, 5 mm captive screw connector is used to connect the amplifier to the speakers.

The recommended MPA 122 output set-up includes 4 ceiling speakers of 8 ohm impedance, (2 sets in parallel with each other), so that each output drives a maximum of 4 ohm loads.

Do not tie both L and R outputs to each other and/ or to input ground. Doing so will short out the outputs and damage the amplifier.

Front Panel Features

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Figure 2-8 — MPA 122 front panel

2-8 MPA 122 • Installation and Operation

1Power LED — A green LED lights to indicate that the unit is receiving power.

2DIP switches — This 2-bank DIP switch controls the limiter (on and off) on one side, and allows for setting the Stereo and Dual Mono modes on the other.

1— Limiter — When the limiter is switched to on, the MPA will automatically reduce the level to prevent the amplifier from clipping.

2— Stereo/Dual Mono:

Stereo mode — In stereo mode, the audio signal input from each channel will be output to the speakers respectively.

Dual Mono mode — In dual mono mode, the inputs from channels L and R will be summed together and output to the speakers as two mono channels. In essence, output L and R contain the same combined signal information.

3Potentiometer adjustments — These three potentiometers optimize level, bass, and treble adjustments.

Setting Up the MPA 122 Amplifier

The following steps ensure optimal sound by adjusting the projector volume to match the level, bass, and treble of the MPA 122 amplifier.

When setting up volume control, ensure that the projector output is set to variable out. Consult the projector’s user manual for detailed instructions on its calibration.

To adjust the MPA 122 input level, bass, and treble, do the following:

1.If connecting to a projector, ensure that the volume on the device is at its lowest point, then adjust the level of the MPA 122 fully counterclockwise.

2.Set the projector volume to its maximum volume level. No sound should come out.

3.Return to the MPA and raise the level until sound distortion occurs, then lower the level slightly until any distortion disappears. This setting ensures that, whatever the projector volume setting may be, no clipping occurs.

4.Adjust bass and treble to preference.