Connecting Power; Using Your Amplifier - Radio Shack MPA-125 Owner's Manual

32-2003.fm Page 12 Tuesday, March 28, 2000 10:45 AM
Follow these steps to connect speakers using a transformer.
Connect a wire from
70V RMS
the amplifier to the transformer's desired pri-
mary tap (10, 5, 2.5, 1.25 or 0.62 watts).
Note: Usually, each speaker in a system
uses the same wattage tap. If you want a
particular speaker to have a higher volume
level, connect the wire from
higher wattage tap on the transformer.
Connect a wire from
COM
amplifier to the (common) taps on the
C
transformer's primary side.
Connect a wire from the speaker's positive
(+) terminal to the transformer's secondary
tap that matches the speaker's total imped-
ance (4 ohms, 8 ohms, or 16 ohms).
Connect a wire from the speaker's negative
(–) terminal to the C (common) tap on the
transformer's secondary side.

CONNECTING POWER

To connect the amplifier to power, plug its
power cord into a standard AC outlet.
Your amplifier's fuse (located on the amplifi-
er's back panel) protects the amplifier from
voltage surges. If the PROTECTION indica-
tor does not light when you press
(see "Using Your Amplifier" and "Safety Indi-
cators" on Page 13), check the fuse. If it is
blown, see "Replacing the Fuse" on Page 17.
12

USING YOUR AMPLIFIER

on the back of
Press in
Start the input sound source.
Rotate
to a
70V RMS
One at a time, adjust
4/PHONO
and balance.
on the back of the
Note: If you hear feedback after you adjust
these controls, turn
wise until the noise disappears (see "Using
the Feedback Filter" on Page 14).
After you get the desired balance, adjust
MASTER VOLUME
el.
POWER
Connections
to turn on the amplifier.
POWER
to its mid-position.
MASTER VOLUME
,
MIC 1 MIC 2
, and to the desired volume
CD/AUX
FEEDBACK FILTER
to the desired volume lev-
, ,
MIC 3 MIC
clock-