Connecting Speakers - Radio Shack MPA-50 Owner's Manual

32-2002.fm Page 7 Friday, February 11, 2000 11:36 AM
determine if your speakers are connect-
ed in series, parallel, or series/parallel
combined.
Note: We recommend that you use
speakers that are rated the same (for
example, all 8-ohm speakers) for all se-
ries or parallel connections.
• Speakers are connected in series
when the first speaker's positive ter-
minal is connected to the next
speaker's negative terminal. Deter-
mine the total impedance of speak-
ers connected in series by adding
up the individual impedances of all
the connected speakers.
For example, if you want to connect
two 8-ohm speakers in series, add 8
(the impedance of one speaker)
plus 8 (the impedance of the other
speaker) for a total speaker imped-
ance of 16 ohms.
• Speakers are connected in parallel
when all their negative terminals are
connected together and all their
positive terminals are connected
together. For speakers rated the
same, find the total impedance of
speakers connected in parallel by
dividing the impedance of one
speaker by the number of speakers.
For example, if you want to connect
two 8-ohm speakers in parallel,
divide 8 (the impedance of one
speaker) by 2 (the number of speak-
ers) for a total speaker impedance
of 4 ohms.
• If you connect more than two speak-
ers using only series or only parallel
connections, the total impedance
might exceed the amplifier's maxi-
mum impedance (16 ohms) or fall
below its minimum impedance (4
ohms).
For example, if you connect four 8-
ohm speakers:
– In series, the total impedance is 32
ohms (8 + 8 + 8 + 8 = 32). This
exceeds the maximum rating.
– In parallel, the total impedance is 2
ohms (8
the minimum rating.
You can arrive at a proper total
impedance by combining series and
parallel connections.

CONNECTING SPEAKERS

You need speakers and wire (available
at your local RadioShack store) to com-
plete the connections to your amplifier.
Be sure to use 16-gauge wire or heavi-
er. (The smaller the gauge number, the
heavier the wire.)
Remove about 1 inch of insulation from
both ends of each wire. Then twist the
exposed wire to secure all its strands.
Connect the speaker wire to the amplifi-
er by pressing down on the appropriate
push terminal tab and inserting the end
of the twisted wire into the terminal's
hole. Then release the tab to secure the
wire.
You can connect one or more 4-, 8-, or
16-ohm speakers, with or without trans-
formers, between the amplifier's output
and the speakers' input. To ensure
equal volume from each speaker, all the
connected speakers should have the
same impedance rating.
Speakers
4 = 2). This falls below
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