Owner`s manual

Echo Effect
You can increase the echo effect by adjusting the
volume with Low (Lo) and High (HI) and mixing with
the Time Delay (DLY) and Repeat (RPT).
GENERAL CONSIDERATIONS
AC Power Distribution
The majority of AC outlets encountered in homes
and clubs are served by a 240VAC center- tapped
service entrance transformer. This provides two phases
of AC power on either side of the center tap at 120V
each. In order to minimize ground loops, the safety
grounds for all the outlets should be connected to a
common ("star") grounding point, and the distance
between the outlets and the common grounding point
should be as short as possible.
If lighting is used in a show, it is preferable to
power the lights from one leg of the service, and
power the audio equipment from the other leg. This
will help minimize noise from the lights coupling into
the audio.
W hen setting up for a show, oftentimes you are
plugging into an AC power distribution system you
know nothing about. You may even be faced with
2-wire AC outlet tester in your toolbox so you can
check the outlets yourself to make sure they are wired
correctly. These testers will tell you if the polarity of the
hot and neutral wires is reversed and if the safety
ground is disconnected. Don't use an outlet if it is
wired improperly! This is to protect yourself as well as
your equipment.
If you find that you must plug into a two-wire outlet,
you will need to use a two-wire to three-wire adapter
(cheater plug). These come with a metal tab that you
put underneath the center screw that holds the AC
outlet faceplate in place. This center screw must be
grounded. You can check it by connecting the adapter
to the outlet and then plugging in your AC outlet tester.
Input Wiring
Use a high-quality 3-conductor shielded cable to
connect the signal between the signal source and the
balanced inputs to the amplifier. If you're using the
unbalanced inputs, use a high-quality 2-conductor
shielded cable.
Output Wiring
Use heavy gauge, stranded wire for connecting
speakers to the MA-930 terminals. As the distance
between the amplifier and the speakers increase, the
thickness of the wire should also increase. Speaker
wire has resistance, and when electricity passes
through a resistor, power is lost. The thicker the wire,
the less resistance it offers, and the more power
actually gets to the speakers.
The thickness of wire is rated in gauges. Use the
chart below to determine the correct gauge of wire to
use according to the distance between the speakers
and the amplifier, and the impedance of the load the
amplifier is driving. This ensures that the power lost
across the speaker wire is less than 0.5dB.
6
WIRE
LENGTH
Up to 25 ft
Up to 40 ft
Up to 60 ft
Up to 100 ft
Up to 150 ft
Up to 250 ft
LOAD
IMPEDANCE
2
4
8
2
4
8
2
4
8
2
4
8
2
4
8
2
4
8
GAUGE OF WIRE
14 gauge
16 gauge
18 gauge
12 gauge
14 gauge
18 gauge
10 gauge
12 gauge
16 gauge
8 gauge
10 gauge
14 gauge
6 gauge
8 gauge
12 gauge
4 gauge
6 gauge
10 gauge