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OHMS.

Discussion in 'Amps and Cabs [BG]' started by The Sound of the Police, Jan 21, 2001.


  1. Hey,
    I apologize for posting another ohms question. I'm sure you get these a lot.
    I got a GK 400RB head and a SWR Working Man's 4x10 cab. The head says 4 ohms into each channel and the cab has 8 ohms. They are both used, and when I was buying it I specifiacally asked if the head and the amp would work together with the impedence. They said yes. My bass teacher, however, said that he thinks you need the same ohms. The combination sounds great and it is plenty loud. So is there a problem or not?

    Thanks for any help

    Kenan O'Brien
    The Sound of the Police
     
  2. Bob Gollihur

    Bob Gollihur GollihurMusic.com

    Mar 22, 2000
    New Joisey Shore
    Big Cheese Emeritus: Gollihur Music
    Hopefully your bass teacher knows more about playing and teaching bass than amplifying one.

    A higher impedance cabinet (8 ohms) than what your amp can handle (4 ohms) is ok. It's the other way around where there can be a problem -- you do not want your speaker load to be lower than the minimum inpedance for your amp.

    If you wired two 8 ohm cabinets together, in parallel (daisy-chaining them, plugging one into the other) the speaker impedance would be 4 ohms, also acceptable to your amp.

    The only potential disadvantage with solid state (not tube) amplifiers, is that they will not deliver their highest power rating to a higher impedance load.

    As an example, the current GK 400RB-III model is rated at 240W into a 4ohm speaker load, and 150W into an 8ohm load. Since you are ok with the volume, it's a "who cares?" and just for your information.
     
  3. oo0o00o0oo

    oo0o00o0oo

    Apr 30, 2000
    Chicago
    Your teacher is said it wouldn't work? Well he's wrong. You can still add another 8 ohm cabinet to your setup, for a total load of 4 ohms on the amp.

    Sorry if this is incomprehensive, been cramming for finals all weekend and I'm beat. It'll work just fine, underpowered even.
     
  4. Thanks a lot for both of your help.

    I know what you mean about those finals.

    Kenan Sugar O'Brien
    The Sound of the Police
     
  5. KillMary

    KillMary

    Jan 25, 2001
    By the way, setting up another cabinet in parallel means using a second output from your amp (they usually have two), and NOT plugging it into the speaker's out. The speaker's out will give you a serial connection, not parallel.
    I hope I'm not scr*wing up on this one :)
     
  6. Bob Gollihur

    Bob Gollihur GollihurMusic.com

    Mar 22, 2000
    New Joisey Shore
    Big Cheese Emeritus: Gollihur Music
    Unless a cabinet's second jack is a special type that has been very specifically wired to break the other jack's connection and set up a serial connection with another cabinet, it is parallel to the other connection. While I have wired special purpose monitor cabinets to act in that way, I have never seen a standard amp cabinet wired that way.
     
  7. This is wrong, see the above post.

    Chris