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Ohms???

Discussion in 'Amps and Cabs [BG]' started by zoxbassist, Dec 13, 2003.


  1. zoxbassist

    zoxbassist

    Dec 13, 2003
    Providence, RI
    Can someone please explain to me why I would choose 4 or 8 Ohms for a cabinet? i.e. would I ever use 2 4-Ohm cabs together, each coming out of the 2 outputs from my Eden WT-400? or would 2 8-ohms cabinets be the way? If 4 Ohms is the maximum output from an amp, why would anyone choose 8 Ohms??

    Thanks,
    Dan
     
  2. BillyB_from_LZ

    BillyB_from_LZ Supporting Member

    Sep 7, 2000
    Chicago
    If the amp doesn't put out twice as much power at 4 ohms, the volume difference won't be noticable if you conducted a test using identical 4 and 8 ohm cabinets.

    At 8 ohms the amp is pumping out less current which allows it run cooler and remain a happy amp for a longer period of time.
     
  3. marklinca

    marklinca

    Nov 11, 2003
    So Cal
    Two 8-ohm cabs, each connected to an output on your WT-400 (i.e. "in parallel"), is a 4 ohm load.

    Two 4-ohm cabs, each connected to an output on your WT-400 (i.e. "in parallel"), is a 2-ohm load. I think the Eden can handle a 2-ohm load, but it will get quite hot (not good for longevity) and most people will not go that route.

    You could put two 4-ohm cabs in series (head out to cab in, cab out to other cab in) to get an 8-ohm load, but you would be driving two cabs with a reduced 8-phm output (250w for the WT-400?) - probably not a good result.

    If you plan to use your WT-400 alone with one cab for some gigs, and two cabs for other gigs, you probably will want to go with 8 ohm cabs.

    As an alternative, you might choose to get 4 ohm cabs and buy a good quality stereo power amp (good bang for the buck these days), which could drive each cab with good power at 4 ohms. You could still use the WT-400 as the preamp. For one cab gigs, just go with the WT-400.
     
  4. Hategear

    Hategear Workin' hard at hardly workin'.

    Apr 6, 2001
    Appleton, Swissconsin
    There are plenty of TalkBassers (myself included) that have been runnning 2-ohm loads for years without any problems. In fact, both of my rigs are rated to run at 2 ohms. If your amp is rated to run at 2 ohms, there will be no problem doing so.
     
  5. Just a note: Two 4 ohm cabs is going to create a 2 ohm load... not 8 ohms!

    :bassist:
     
  6. Richard Lindsey

    Richard Lindsey

    Mar 25, 2000
    Metro NYC
    Well, he was technically right--he said *in series*, and that's correct, impedances are added in series. With a *parallel* connection, you would be correct: 4 + 4 = 2 in that scenario.

    The problem is that unless he's envisioning an unconventionally wired cab, the daisychaining he described is *not* in fact a series connection but a parallel one. The two jacks on most cabs are wired in parallel.
     
  7. marklinca

    marklinca

    Nov 11, 2003
    So Cal
    Wow - I stand corrected on the parallel/series for daisy chaining. It looks like I have been fed some bad info by people that should know better. Perhaps particular brands (Genz-Benz was my recent experience that perpetuated the myth) have the jacks in series? Thanks for the info!
     
  8. Richard Lindsey

    Richard Lindsey

    Mar 25, 2000
    Metro NYC
    Conceivable, I guess, but I don't know of any.
     
  9. tkarter

    tkarter

    Jan 1, 2003
    kansas
    Now I am confused should I be running from the head to each of my two 8 ohm cabs to get the 4 ohms I am looking for?

    tk
     
  10. In the owners manual for my Eden 4-10, it has a really great diagram and table for configuring cabs. It states: Two 4 ohm cabinets in a series speaker configuration will be a total system impedance of 8 ohms. The figure recommends using banna plugs and routing the signal as follows:

    + on the amp to + on speaker 1
    - on speaker 1 to + on speaker 2
    - on speaker 2 back to the - on the amp.

    Haven't tried it though as I'm pretty pleased with the stereo WT500 as it is.

    It is a good idea to always check your owners manual.

    Andy
     
  11. what you want to do is daisy chain your two cabinets off of ONE output from the amp i.e. amp output to cabinet then connect the first cabinet to the second cabinet ..... from the perspective of the output of the amplifier, this will look like a four ohm load which will make it very happy :D
     
  12. amos

    amos

    Oct 23, 2003
    SE Portland Oregon
    YES, that is the other option besides daisy chaining. just make sure that if you run a separate power amp it is set to parallel mode.
     
  13. tkarter

    tkarter

    Jan 1, 2003
    kansas
    Thanks rather than running from my amp to both cabs I have been running from the amp to my 2x10 cab then the 2x10 cab out to the 15 cab. I thought that was the correct way to get the 4 ohms.

    tk
     
  14. Richard Lindsey

    Richard Lindsey

    Mar 25, 2000
    Metro NYC
    Either that or daisychain them, it doesn't matter.
     
  15. Oh, that's rich. Nothing like a little "juice"!!!!

    LOL
    :p
     
  16. Whappo Grande

    Whappo Grande

    Feb 9, 2002
    Santa Clara, CA.
    Manager: AccuGroove Speakers
    In trying to solve this problem, a company I know will be introducing the AccuSwitch at the NAMM show in a couple of weeks.

    It will be a standard feature on their medium to large cabinets so you can change from 4 to 8 Ohms by flicking a switch. There is no change in volume or sound.

    Mark
    AccuGroove.com
     
  17. Whappo Grande

    Whappo Grande

    Feb 9, 2002
    Santa Clara, CA.
    Manager: AccuGroove Speakers
    In trying to solve this problem, a company I know will be introducing the AccuSwitch at the NAMM show in a couple of weeks.

    It will be a standard feature on their medium to large cabinets so you can change from 4 to 8 Ohms by flicking a switch. There is no change in volume or sound.

    Mark
    AccuGroove.com
     
  18. sounds rather logical. I wonder why no one else has thought of that?

    So...who is this company? I'd like to try some of their stuff. But.... I'm awfully happy with my "EL Whappo"!! so I'd be hard pressed to change to another manufacturer:cool:
     
  19. Whappo Grande

    Whappo Grande

    Feb 9, 2002
    Santa Clara, CA.
    Manager: AccuGroove Speakers
    You wouldn't have to.

    Mark
    AccuGroove.com