OHMS questions

Discussion in 'Amps and Cabs [BG]' started by BLonge, Jan 9, 2005.

  1. BLonge


    Jan 8, 2005
    this whole ohms thing is kind of confusing since im new to all of this, and i dont want to spend hundreds of dollars on equpiment just to have it catch on fire.

    so how i understand it is, the head im looking at (swr workingman 4004) can run under 4 or 8 ohms. the cab im looking at (ashdown 4x10) is rated for 8. therefore, i should have the head playing at 8 ohms and theyll work fine. now, what if i got a 1x15 rated for 4 ohms. the head runs 260 watts under 8 ohms and the 4x10 can handle 300, so i guess its good to have some head room. however, if i add more cabs, will i be able to run the head at 4 ohms, giving me 400 watts and not harm any of the cabs??

    im no electrician
  2. The 115 should be 8ohms, 8ohms + 8ohms = 4ohms which is what you want, not 8ohms + 4ohms = 2.66ohms or something, which would fry your amp and not sound good anyway.
  3. Tritone

    Tritone Gold Supporting Member

    Jan 24, 2002
    Santee, America
  4. If you got just the 4 ohm 1x15 you'd also be fine, but yah you couldn't run both of them at the same time.

    And headroom is more applicable to amps then to cabs - ie) so you only have your amps volume on 4 instead of 10 when you're playing with a loud group.
  5. BLonge


    Jan 8, 2005
    answers breed more questions:

    so i should get a head that can put out more watts than my speakers can handle so i don thave to turn it all the way up.

    at the moment im looking at a yorkville Bass Head with Tube Preamp and it doesnt say andything about ohms,just that it puts out 400 watts. what does this mean? will it be ok with any cab? ive seena few heads that dont specify ohms.

    basicly,right now i need a set up that is cost effective, and can be heard over the guitarists new mesa boogie guitar head and be heard in my school's auditorium. my band is opening for zox ( http://www.zoxband.com/ ) when they come to my school in march. so would the swr 4004 running at [email protected] with the ashdown 4x10 be enough?
  6. You should buy the workingman head and a 1x15 cabinet that's also 8ohms, then you will be able to run both your 1x15 and you 4x10 at once with your workingman 4004 running at full potential.
  7. BLonge


    Jan 8, 2005

    yeah thats what i was planning, get the head and the ashdown 4x10 then later on when i get more cash,ill get the ashdown 1x15. those blue speakers look sharp. :smug:
  8. Happy MurphDay

    Happy MurphDay

    Mar 9, 2004
    where is IvanMike and his guide
  9. Not necessarily... but having enough watts to have your amp loud enough while running it at '4' is better than having to run in at '10' to be heard. If you had room to spare on both of them that would be ideal IMO - but the head is more important.

    Ask a customer service guy or check with Yorkville... Ohms will matter regardless of the head.
  10. IvanMike

    IvanMike TTRPG enthusiast, Happy, Joyous, & Free. Supporting Member

    Nov 10, 2002
    Middletown CT, USA
    usually when all a head says is "it's X - watts", you can bet that's at 4 ohms. if you need more volume, get another 8 ohm speaker like a 15 or 210. You'll notice more volume increase than if you got more watts, (unless you got a ton more watts)
  11. Bob Lee (QSC)

    Bob Lee (QSC) In case you missed it, I work for QSC Audio!

    Jul 3, 2001
    Chester, Connecticut
    Former Technical Communications Developer, QSC Audio
    "Turning all the way up" has nothing to do with how much power the amp can put out.
  12. ceycey


    Dec 22, 2004
    Maybe it's a different question according to the subject but i don't want to open anymore thread on ohms.

    Is there any chance to run two 4 Ohm cabinet together with 4 ohm?
    For example: If i buy a 450w at 4 ohm, 275w at 8 ohm power amp and want to use two 4 ohm cabinets like 2x10 and 1x15, can i run them totally in 4 ohm? I'm asking this because the power amp can't produce 2 ohm.
  13. Richard Lindsey

    Richard Lindsey Supporting Member

    Mar 25, 2000
    SF Bay Area
    Unfortunately, no, you can't.
  14. ...unless you daisy chain them.
  15. IvanMike

    IvanMike TTRPG enthusiast, Happy, Joyous, & Free. Supporting Member

    Nov 10, 2002
    Middletown CT, USA
    actually daisy chaining the cabinets results in a parallel hookup as well. you need to get special cables to hook them up in series
  16. Richard Lindsey

    Richard Lindsey Supporting Member

    Mar 25, 2000
    SF Bay Area
    No, not then either--that's still a parallel connection. You cannot get 4 and 4 to add up to 4.

Share This Page