Radio Shack MPA-125 - Manual (Page 9)

9 Connections
You can achieve a proper total impedance
by combining series and parallel connec-
tions.
Preparing the Speaker Wire
Use the shortest length of wire possible to
connect the speakers. After placing the
speakers, use this table to determine the
wire length and choose the appropriate
gauge size:
Note: If you connect speakers without trans-
formers, the speaker wire should be no long-
er than 50 feet (see “Connecting Speakers
with Transformers” on Page 11).
To prepare the speaker wire, remove about 1
inch of insulation from the end of the speaker
wire you are connecting to the amplifier.
Then twist the exposed wire to secure all of
the wire strands.
To connect speaker wire to the amplifier,
press the push terminal lever on the amplifier
for the connector you want, insert the end of
the wire into the terminal’s hole, then release
the lever to secure the wire.
Connecting Only One Speaker
Connect the speaker’s negative (–) terminal
to
COM (common) on the back of the amplifi-
er. Then connect the speaker’s positive (+)
terminal to the speaker terminal (
4
Ω Ω Ω Ω
, 8
Ω Ω Ω Ω
, or
16
Ω Ω Ω Ω
) on the back of the amplifier that match-
es the speaker’s impedance.
Connecting Two Speakers In
Series
Follow these steps to connect speakers in
series.
1. Connect the left speaker’s positive (+)
terminal to the right speaker’s negative
(–) terminal.
2. Connect the left speaker’s negative (–)
terminal to COM on the back of the
amplifier.
3. Connect the right speaker’s positive (+)
terminals to the speaker terminal ( 4 Ω Ω Ω Ω ,
8
Ω Ω Ω Ω
, or 16
Ω Ω Ω Ω
) on the back of the amplifier
that matches the total speaker imped-
ance.
Wire Length Wire Gauge
25 feet or less 18 gauge
Over 25 feet 16 gauge
Terminal Levers
8 Ω Ω Ω Ω Speaker
Left Speaker
Right Speaker
32-2003.fm Page 9 Tuesday, March 28, 2000 10:45 AM