8ohm and 4ohm speaker question

Discussion in 'Home Cinema Speakers' started by shoehorn, Apr 24, 2007.

  1. shoehorn

    shoehorn
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    I have an amp with this spec:
    50W minimum RMS per channel (8 Ohms, 20-20kHz, THD+N < 0.02%)
    Can I run one set of 8 ohm speakers and one set of 4 ohm speakers from it, or will I cause damage?
    (the amp is the inbuilt one from the Sonos ZP100 - here)
    Thanks.
    :)
     
  2. Nobber22

    Nobber22
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    It's not a good idea to run 2 sets of 8ohm speakers from one amp(let alone a set of 4ohm ones too). You put too much strain on a stereo amp running 4 speakers, which will probably lead to it under-driving both pairs of speakers and damaging them.

    If you want to run 2 pairs, you should get a second amp. :lesson:
     
  3. shoehorn

    shoehorn
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    I hear you.... but they are £379 each ! (and SWMBO will notice ! !)
    I thought they could be run in parallel ?
    I just wanted to know if I could mix 8 and 4 ohms ?
     
  4. Nobber22

    Nobber22
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    Welllllllll.......I suppose you can, but you better keep the volume low. Can you do that when your favourite track comes on, while some friends are visiting and you want to "Get The Party Started" ? ;)

    Surely you can run a line out from the Sonos to a budget stereo amp that can drive the second pair of speakers? :confused:
     
  5. Nimby

    Nimby
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    When running speakers in parallel it is dead easy to see what the final (nominal) impedance will be.

    1/8 + 1/4 = 1/0.375 = 2.666 Ohms. A bit less than 3 Ohms!

    2.6 Ohms will fry most amps not designed for it!

    Most aren't.

    Don't even think about it or your amp's heatsinks will be glowing in the dark!

    If you have Pre-out phono sockets on your present amp you can connect those to a cheap old stereo amp to drive one pair of speakers. (as mentioned already)

    Some charity shops have old Japanese stereo amps selling for pocket money prices. Not all do. Or have them all the time.
     
  6. shoehorn

    shoehorn
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    OK - so how about if I run two sets of 8 ohm speakers?
    - and what about speaker splitters?
    - something such as this?

    Could I run the inbuilt Sonos amp with 4 ohms (2 lots of 8 ohm speakers, right ? ) ?

    I appreciate your help guys - I'm not really up to speed with all this - it's been 20 years since physics for me ! !

    Just don't want to break anything (including the bank for another Sonos!)
     

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