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100v line and 8ohm?????

Discussion in 'Home Cinema Speakers' started by jon114, Jun 23, 2005.

  1. jon114

    jon114
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    could anyone explain in idiots english what the difference between a 100volt line speaker and an 8 ohm speaker is and which applications they should be used in

    any help appreciated

    thanks
     
  2. MarkE19

    MarkE19
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    Basically a 100v line is used when there is a large distance between the amp and the speakers, ie in a church.
    You would plug the speaker outputs from the amp into a box that will convert the signal to 100v and pass along the 'long' speaker cable to the speakers. At the speakers you will have either a separate box with a transformer to take the signal back to standard voltage for the speaker, or the speaker can have the transformer built in.

    8ohm are the standard rating for many AV/HiFi systems and this is the load that the speaker puts on the amp that is driving them. Even useing 100v line you would still have speakers of 4 or 8 ohms.

    Mark.
     
  3. jon114

    jon114
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    thanks a million i thought it had something to do with distance
     
  4. Reiner

    Reiner
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    100V is used in PA (public announcement) systems where you have many speakers (tens or even hundreds) connected to one source, like playing music in a department store.
    The 100V speakers are not compatible to consumer hifi/AV stuff, at least not without modification.
     
  5. MarkE19

    MarkE19
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    The 100v line system is used to prevent signal loss over long lengths of speaker cable, it is not used to drive multiple speakers as the signal is converted back to its standard voltage before being fed to a speaker.
    As previously stated, you have a transformer at both ends of the speakers cable(*), so by the time the signal is fed into a speaker it is exactly (or as close to as possible) the same as the direct output from the amp. Connecting a speaker directly to a 100v signal would be the same as connecting a speaker to the mains supply in the USA (110v), and I doubt many people would even consider doing that - I hope! So as Reiner said, 100v line is not directly compatable with AV/HiFi speakers without the external transformers on either end of the speaker cable(*).

    * when I say speaker cable I mean the cable carrying the audio signal, and not standard speaker cable!

    Mark.
     
  6. GaryB

    GaryB
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    I have seen the results of connecting a normal speaker to a 100v line. It's a very loud rasp from the speaker followed by a puff of smoke as the voice coil fries. The guy that did it got a bit of a shock!
     
  7. Steve.EX

    Steve.EX
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    What did he think would happen?
    Tell him to try 3 phase next time. The resultant shock will ensure complete removal from the gene pool.
     

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