quick speaker ohmage questions

Discussion in 'Amps and Cabs' started by re-animator, Jan 29, 2008.


  1. re-animator

    re-animator Senior Member

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    hi, i've got a vox ac30cc2 and it operates at 8 ohms normally (both of the internal speakers are also 8 ohms a piece), but you can set the ohmage to 16 for an extension cab.


    I scored a 16 ohm weber speaker in the emporium... obviously i need 1 more speaker though.


    - will it work in the cab as long as I set the amp to 16 ohms??? i.e. 2x16 ohm speakers in a cab set to 16 ohms??


    - does the second speaker also have to be 16 ohms, or will 8 ohms work??


    - will 2x16 ohm speakers work with an amp set to 8 ohms, or is it the other way around?
     
  2. welcometoashley

    welcometoashley Supporting Member

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    i think if you were to switch to two 16ohm speakers the amp setting would depend on how you wire the speakers (series vs parallel).

    So, 2 x 16ohm speakers wired in parallel, the amp would need to be set at 8ohms.

    2 x 16 ohm speakers wired in series, the amp would need to be set at 16 ohms....

    can anyone else confirm??
     
  3. drbob1

    drbob1 Silver Supporting Member

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    Ummm, there's a false assumption starting here. The CC2 uses 2 16ohm speakers in parallel for a total of 8 ohms. If you have two 16 ohm speakers in your extension cab, you'll have either 8 ohms (parallel) or 32 ohms (series) there. Now your choices are, run only the external cab at 8 ohms; run both cabs with a series adapter (not a simple solution) for 16 ohms; run both sets of speakers plugged into the usual jacks on the amp for 4 ohms, which should be safe with the amp set for 4 or 8 ohms...
     
  4. bendix

    bendix Member

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    I am curious how the internal speakers are coming out at 8 ohms each and yet the amp is set to 8 ohms. If you connect two 8 ohm speakers in series, the resulting circuit will be 16 ohms. If those same speakers are connected in parallel the circuit will measure 4 ohms.
    If you wire two 16 ohm speakers in series, the resulting circuit will be 32 ohms. The output transformer should be set so it works correctly with the speaker load presented to it, so I think that you should get another 16 ohm speaker, wire the pair in parallel, (giving you an 8 ohm load,) and set the amp to 8 ohms.
    Unless there is something else connected in the cabinet that is not being mentioned, that is how I would do it.
    Tim
     
  5. EADGBE

    EADGBE Member

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    Make sure everything matches or you could blowup the amp.
     
  6. mcdes

    mcdes Member of no importance

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    umm, vox 2 x 12's normally come with two 8 ohm speakers in series, which needs the amp to be set at 16ohms. of course, you can do whatever sounds best to ya.

    if you get two 16 ohm speakers it will prob be best to wire in parrallel and set to 8 ohms as stated above.
     
  7. re-animator

    re-animator Senior Member

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    yeah, my bad, the amp is set up at 16 ohms and the speakers are 8 (i can't read good :p )


    so is it still possible to use a pair of 16 ohm speakers (in the cab) instead of 8s?? that's the question i'm really askin.... need to know quick because I'm about to send out cash for a 16 ohm weber in the emporium!
     
  8. re-animator

    re-animator Senior Member

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    bump... i need to know like within minutes guys.
     
  9. hamfist

    hamfist Member

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    Yes .... if you can set your amp to require an 8 ohm load (two 16 ohm speakers wired in parallel give an 8 ohm load).
     
  10. re-animator

    re-animator Senior Member

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    that's an affirmative :)
     
  11. E-Rock74

    E-Rock74 Member

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    Unless I am mistaken (always a possibility), I think you will only be able to use two 16-ohm speakers mounted in an extension cabinet with your amp if you do not wish to use the internally-mounted speakers that are already in the combo.

    If you wire two 16-ohm speakers in series, the impedance of the extension cab will be 32-ohms. If you wire two 16-ohm speakers in parallel, the impedance of the extension cab will be 8-ohms. According to the user manual, you can use an 8-ohm extension cab, but you must use the External jack on the amp chassis, thereby muting the speakers currently mounted in your combo.

    Quoted from p. 8 of the AC30CC user manual:

    1) Loudspeaker Output Jacks: This is where you can hook up an extension or external speaker cabinet(s) if desired.

    Note! Hooking up a cabinet through the External jack will mute (disconnect) the internal speakers!

    Extension: This speaker jack runs parallel with the internal speakers which are wired for 16 Ohms. The extension cabinet must be 16 Ohms.

    External: This speaker jack will mute (disconnect) the internal speakers and you can hook up either a 16 Ohm or 8 Ohm cabinet. Be sure to set the Output Select switch accordingly.
     

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