Figure 2-9 — Output speaker wiring

Installation and operation, cont’d

4/8 ohm output

70 volt output

 

 

 

 

COM 70V

 

 

 

 

COM 70V

70V

 

70V

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

4/8 OHM

+ -

4/8 OHM

+ -

+

COM 70V

Figure 2-9 — Output speaker wiring

The 70 volt output and the 4/8 ohm output cannot be used simultaneously.

Front Panel Features

ON

LEVEL

BASS

TREBLE

1

LIMITER

OFF

MPA 181T

MINI POWER AMPLIFIER

23

Figure 2-10— MPA 181T front panel

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

2Limiter toggle switch — When the limiter is switched to “On”, the MPA will automatically reduce the level to prevent the amplifier from clipping.

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

Setting Up the MPA 181T 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 181T 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 181T 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.

Remote connector wiring

Options for remote control include the Extron VCM 100 and VC 50 volume controllers. Third party 10k potentiometer volume controllers can also be connected to this port.

As shown below, Pin 1 is 10 VDC reference voltage. Pin 2 is volume control DC voltage; range is 0 to 10 V, where 0 V is mute and 10 V provides maximum volume. Pin 3 is ground.

All nominal levels are at ±10%.

 

 

 

 

 

 

Red

 

 

 

 

Extron

 

 

 

 

 

 

Black

 

 

 

 

REMOTE

 

 

 

 

Ground

 

 

 

 

STP 22

 

 

 

 

 

 

 

 

 

 

Cable

 

 

 

 

 

 

 

 

 

 

 

1

2

3

10V

VOL/ MUTE

10V

VOL/MUTE

VOLUME

MUTE

VCM 100

Figure 2-11— Pinout diagram for VCM 100 MAAP remote connector

2-10

MPA 181T • Installation and Operation

MPA 181T • Installation and Operation 2-11

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Extron electronic user manual Front Panel Features, Setting Up the MPA 181T Amplifier, Remote connector wiring, 2-10