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Impedence question

Discussion in 'Amps and Cabs [BG]' started by Jumping_Bomb_Angel, Dec 12, 2005.


  1. I have a Mesa 4x10 Road Ready cab, 600W, 8 Ohms.

    Can I run this cab safely with a 4 ohm amp?

    Suggestions/advice please.
     
  2. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
     
  3. tadawson

    tadawson

    Aug 24, 2005
    Lewisville, TX
    There is no such thing as a 4 ohm amp! There are amps rated for a MINIMUM load of 4 ohms, which will drive 4 and anything greater . . . . .

    - Tim
     
  4. Aren't all tube amps different?
     
  5. thats what i was going to say . . . SVT's are only 2 and 4 ohm
     
  6. If you are asking about your Carvin R1000 the short answer is you'll be fine with an 8 ohm cab.

    For for info check the FAQ sticky at the top of this forum.
     
  7. Now I am really confused...
     
  8. Looks like we posted at the same time! HEY OVER HERE! CHECK YOUR THREAD AGAIN! :D
     
  9. georgestrings

    georgestrings Banned

    Nov 5, 2005

    OK, short answer to your question: yes


    As to what Bill's referring to:


    FAQ link


    - georgestrings



    PS - I hear ya, Bill....
     
  10. IvanMike

    IvanMike Player Characters fear me... Staff Member Supporting Member

    Nov 10, 2002
    Middletown CT, USA
    the ohms faq confusing????????????? :D

    anyhow, a solid state amp will be fine with any load at or ABOVE the minimum impedance it can handle. most SS amps can safely power a 4 ohm load minimum, a lot these days can handle a 2 ohm load minimum.

    a tube amp wants to have exactly the impedance that it's set for. some have settings for 8, 4 and 2 ohms, but a lot only have settings for 4 and 2. In theory, you're reasonably safe with a 100% margin of error either way, so a tube amp set for 4 ohms can be run into a 2 ohm load or an 8 ohm load. But.....................


    unlike solid state amps which are ok into any impedance at or above their stated minumum, tube amps actually do worse when run into an impedance higher than what they are set for. A tube amp set for 4 ohms run into an 8 ohm load will have the plate voltage increased, and various components undergo a good amount of stress. I'm not a tube amp guru, and other cats on the site can go into more detail, but suffice it to say that to play it safe you should stick to running tube amps into the exact impedance they are set for.
     
  11. Thanks for all the help. I Emailed Mesa direct, they were a great help - I would recommend their support team.

    I'm going with the MPulse 360 with my Mesa 600w quad. An amazing sound....i've never heard anything like it...