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ohms

Discussion in 'Amps and Cabs [BG]' started by Pthump, Jun 27, 2005.


  1. Pthump

    Pthump

    Nov 18, 2004
    I have no idea what this means :( Im looking into getting an avatar cab, dunno whether to get a 4 or 8 ohm. My head is a SWR workingmans 400 watt.. I plan to add another cab later, so which do i want.
     
  2. Plain Old Me

    Plain Old Me

    Dec 14, 2004
    Do a search. I think there is a tech page on here somewhere as well. If you want to add another cab later, get 8 Ohms.
     
  3. Lowtonejoe

    Lowtonejoe Supporting Member

    Jul 3, 2004
    Richland, WA
    You need to know your amps nominal impedance. They can all do 8ohms, most do 4ohms and some can do 2ohms. If your amps nominal impedance is 4 ohms you may use 2-8ohm cabs or 1-4ohm cab.

    :D

    Joe.
     
  4. oldfclefer

    oldfclefer low ended

    May 5, 2005
    Southern Ohio
    If you add a cab, add the impedence of both cabs and divide by 4. If the answer is less than the recommended minimum impedence your amp is specified to run, you can harm the amp. If the answer is greater, you should be fine.
     
  5. A huge discussion of ohms and everything related is here:

    Ohms FAQ

    For a somewhat less technical discussion check here:

    How Ohms Work
     
  6. oldfclefer

    oldfclefer low ended

    May 5, 2005
    Southern Ohio
    My formula works for two cabs.
     
  7. you want an 8 ohm cab. it will not get the maximum amount of power from the amp, but it will allow you to add another (8ohm) cab later on.
     
  8. Richard Lindsey

    Richard Lindsey

    Mar 25, 2000
    Metro NYC
    Only if they're the same impedance. By your formula, 8 + 4 = 3, but the accurate answer is 2.67. Close, but no cigar.;) (Actually, close enough for most practical purposes.)
     
  9. oldfclefer

    oldfclefer low ended

    May 5, 2005
    Southern Ohio
    Yes, yes, now I remember. In ohms, it's product divided by sum for parallel cabs.
    Sorry for the mistake.
    Reviving this thread to dispel disinformation.
    Thanks for pointing it out.