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7

Speakers

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 

÷

 4 = 2). This falls below

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.

32-2002.fm  Page 7  Friday, February 11, 2000  11:36 AM

Содержание MPA-50

Страница 1: ...Owner s Manual Please read before using this equipment MPA 50 40 Watt PA Amplifier 32 2002 fm Page 1 Friday February 11 2000 11 36 AM...

Страница 2: ...edance 6 Connecting Speakers 7 One Speaker 8 Two or More Speakers Without Transformers 8 Multiple Speakers with Transformers 10 Controls and Operation 12 Troubleshooting 13 Care 14 Replacing the Fuse...

Страница 3: ...Auxiliary Volume Control lets you adjust the volume of the connected equipment Priority Terminals let you connect an optional switch to cut out all other au dio input sources and give priority to onl...

Страница 4: ...with adequate venti lation Do not place the amplifier on thick carpeting or cushions which can restrict the air flow or near a heat source such as a heat vent or radiator which can cause the amplifie...

Страница 5: ...r turntable to this screw to avoid a low frequency hum You can also use this screw to ground any other system connection PHONO AUX CD Switch Select the input source Even if you connected auxiliary equ...

Страница 6: ...2 Connect one end of the wire to one of the speaker terminals 3 Touch the positive end of a 1 5 volt flashlight battery to the speaker ter minal that does not have the wire attached to it 4 Touch the...

Страница 7: ...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 impedan...

Страница 8: ...d system you must determine the total impedance of the speakers before you can make the correct connection The total impedance of all the speakers must match one of the amplifier s output terminals 4...

Страница 9: ...this example Series and Parallel Combined If you must hook up more than two speakers you might have to use a com bination of series and parallel connec tions to get a total impedance that matches one...

Страница 10: ...require many speakers and long runs of connecting wire we recom mend you use a line transformer not supplied Note When running lengths of wire longer than 50 feet use wire that is heavier than 16 gaug...

Страница 11: ...n necting a 2 5 watt speaker to a transformer connect this wire to the 2 5 tap on that transformer s primary side 2 Connect a wire from the amplifier s COM terminal to the COM tap on each trans former...

Страница 12: ...PHONO AUX Source Mixing Control Adjusts the input level of the PHONO or AUX CD sound source for the best volume and balance 150Hz Equalizer Control controls output for instruments in this very low ra...

Страница 13: ...ker wire You should always use 16 gauge or larger wire The longer the run of speaker wire the heavier the gauge should be If you have feedback problems reposi tion your microphones and speakers or adj...

Страница 14: ...RadioShack store for assistance REPLACING THE FUSE The power fuse protects your amplifier from power voltage or current surges when operating it from an AC power source If the POWER indicator does no...

Страница 15: ...z AUX CD 70 Hz 20 kHz PHONO 100 Hz 12 dB 10 kHz 13 dB Equalizer Control Range at Each Band Peak Point 150Hz 12 dB 1kHz 12 dB 6kHz 12 dB Crosstalk from AUX to PHONO 40 dB Nominal Hum and Noise at 8 Ohm...

Страница 16: ...efect during the warranty period take the product and the RadioShack sales receipt as proof of purchase date to any RadioShack store RadioShack will at its option un less otherwise provided by law a c...

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