Extron Electronics MPA 122 User Guide - Manual (Page 11)

MPA 122 • Installation and Operation MPA 122 • Installation and Operation
Installation and operation, cont’d
4 Balanced 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.
Unbalanced Input
Tip
Sleeve
Tip
Balanced Input
Tip
Ring
Sleeve (s)
Tip
Ring
Figure 2-7 — 3.5 mm captive screw audio input
connector wiring
Remote control
5
Remote 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
6 Speaker 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
BASS LEVEL TREBLE
MINI POWER AMPLIFIER
MPA 122
ON
OFF
LIMITER
STEREO
DUAL
MONO
2 3
1
Figure 2-8 — MPA 122 front panel
1 Power LED — A green LED lights to indicate that the unit is
receiving power.
2 DIP 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.
3 Potentiometer 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.
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