MPA-250 250-Watt Stereo Public Address Amplifier
(320-2004)                 Operation                  Faxback Doc. # 51682

Using Your Amplifier

1.  Start the input sound source.

2.  Make sure LEFT and RIGHT on the front of the amplifier are set to MIN.

3.  Press in POWER to turn on the amplifier.

4.  One at a time, adjust LEFT and RIGHT to the desired volume level.

    Turn LEFT and RIGHT clockwise to increase or counterclockwise to
    decrease the corresponding left and right output power.  To get the
    best performance with the least sound distortion, always adjust LEFT
    and RIGHT so the meter's pointer does not continuously swing to the
    extreme right.

5.  When you finish, press in POWER to turn off the amplifier.

Using the Meters/Meter Range

The position of the pointers on both of the amplifier's meters indicate 
the output power.  Built-in lamps light to make the meters easy to see in 
dark areas.

The METER RANGE button on the front of the amplifier controls both meter's 
sensitivity.  When output power is too strong, a meter's needle might 
continuously swing to the extreme right, damaging or reducing the accuracy 
of the meter.

If the meter's needle continuously swings to the extreme right, set METER 
RANGE to out to maintain a 0 dB gain for the meter.  Or, set METER RANGE 
to in to allow a 20 dB gain.

Clip Indicator

The CLIP indicator on the front of the amplifier lights steadily when a 
sound source's signal exceeds the output power level you set using LEFT 
and RIGHT, warning you of possible damage to the amplifier.  If this 
happens, reduce the output level of the connected sound source or LEFT and 
RIGHT until the indicator flickers only at peak volume levels.

Using Speaker A/B

Press in SPEAKER A or SPEAKER B on the front of the amplifier for the 
channel you want to listen to.  Or, press in SPEAKER A and SPEAKER B to 
listen to all connected speakers.

CAUTION:  If you connected 4 Ohm speakers to the amplifier, do not set
          both SPEAKER A and SPEAKER B to in.

Monitoring The Sound Sources

To monitor the sound sources directly from the amplifier, connect a pair 
of mono or stereo headphones with a 1/4-inch (6.35-mm) plug into the 
PHONES jack on the front of the amplifier.  Using headphones lets you 
easily check and adjust the sound source's balance.

Note:  Your local RadioShack store carries a wide selection of headphones.

Listening Safely

To protect your hearing, follow these guidelines when you use headphones.

  Set the volume to the lowest setting before you begin listening.  After
  you begin listening, adjust the volume to a comfortable level.

  Do not listen at extremely high volume levels.  Extended high-volume
  listening can lead to permanent hearing loss.

  Once you set the volume, do not increase it.  Over time, your ears adapt
  to the volume level, so a volume level that does not cause discomfort
  might still damage your hearing.

(EB 3/4/99)