Radio Shack MPA-50 owner manual One Speaker

32-2002.fm Page 8 Friday, February 11, 2000 11:36 AM

One Speaker Speakers in Series

8Ω Speaker

Connect the speaker’s negative (–) ter- minal to the amplifier’s COM (common) terminal. Then connect the speaker’s positive (+) terminal to the amplifier’s terminal that matches the speaker’s im- pedance. For example, if you have an 8- ohm speaker, connect the speaker’s positive terminal to the amplifier’s 8-ohm terminal.

Two or More Speakers Without Transformers

We recommend connections without transformers if the length of the connect- ing wires between the amplifier and the speakers is 50 feet or less.

When making connections without transformers, all the speakers must have the same impedance rating to en- sure equal volume from each speaker. When there is more than one speaker in a sound 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 (4Ω, 8Ω, or 16Ω).

Two 8Ω Speakers

1.To determine the total impedance of speakers connected in series, add the impedance of all the 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.

2.Connect the first speaker’s positive

(+) terminal to the second speaker’s negative (–) terminal.

3.Connect the first speaker’s nega- tive (–) terminal to the amplifier’s COM terminal.

4.Connect the second speaker’s posi- tive (+) terminal to the amplifier’s

terminal that matches the total speaker impedance (16Ω, in this example).

8 Speakers