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Can I rewire my Ashdown cab to 4 ohms?

Discussion in 'Amps and Cabs [BG]' started by vintageampeg, Apr 25, 2005.


  1. vintageampeg

    vintageampeg Supporting Member

    Feb 2, 2005
    I have a Mag 410T on the way. It's rated at 8 ohms, but I'll be using it as a standalone cab for a little while anyway. For this reason I'm wondering if I can rig the Blueline speakers to 4 ohms so I can get the most power out of my head.

    Anyone familiar w/ the wiring of this cab?
     
  2. You can't re-wire your cabinet, you will need new woofers.
     
  3. vintageampeg

    vintageampeg Supporting Member

    Feb 2, 2005
    Not too surprising. Thanks.
     
  4. Vanagon

    Vanagon

    Nov 13, 2004
    I don't know how this cab is wired and what the individual speaker impedance is, but it could still be a possibility. My guess is there 32ohm speakers wired in parallel, which means your **** out of luck. There is the off chance that they are 16ohm speakers, wired in series and parallel. Which means you could rewire them in parallel to give you your 4ohm load. Might be worthing looking into a bit further.


    P.S. I often don't know what the hell i'm talking about
     
  5. Eric Moesle

    Eric Moesle Supporting Member

    Sep 21, 2001
    Columbus OH
    Your P.S. is right on this one, LOL. Four 8 ohm speakers wired in series/parallel combination equals 8 ohms. If he already has an 8 ohm cab, it can't be 16 or 4, under ANY circumstances.
     
  6. Vanagon

    Vanagon

    Nov 13, 2004

    Not so fast. He said the cab was 8 ohms, not the speakers. Which means if they happen to be 16ohm speakers (and happen to be currently wired series/parallel to achieve 8ohms), then they could be rewired in parallel to achieve 4ohms. If you don't believe me ask Ted Weber, he knows more about speakers than you....

    http://www.webervst.com/sptalk.html

    sixth question down
     
  7. Eric Moesle

    Eric Moesle Supporting Member

    Sep 21, 2001
    Columbus OH
    Its the bold part that is in error. You absolutely cannot have FOUR 16 ohm speakers wired in any configuration to achieve 8 ohms . . . sorry, but I don't care who you quote, the math doesn't work.
     
  8. Vanagon

    Vanagon

    Nov 13, 2004
    Like I said....

     
  9. im going to start this off by saying i doubt i know what im talking about either.

    if you'll look on that site it seems as though wiring 2 of the tens in series and wiring the other 2 in series completelyu seperate from each other would give you a 16Ohm load on each set of 2 speakers. then by wiring those 2 16ohm sets together you would get 8 ohms total.

    if rewiring speakers to new ohm loads was completely impossible then Accugrooves Accuswitch wouldnt be possible, not that i know AT ALL how they pull that off... does anyone?
     
  10. Email Ashdown tech support
     
  11. Rewiring speakers to new ohm loads isn't impossible of course, but rewiring them to get the load you want often is. Since simply rearranging the wiring often doesn't yield the desired result, the Accugroove Accuswitch must be changing the cab impedance by way of the L pads somehow. It's a patented process so I doubt we're going to find out how it's done in much detail.
     
  12. Eric Moesle

    Eric Moesle Supporting Member

    Sep 21, 2001
    Columbus OH
    You're not reading that diagram correctly. What you say WOULD be the case with 8 ohm speakers, but not with 16 ohm speakers. The diagram is NOT presenting 16 ohm speakers in that manner, only 8 ohm speakers.

    Four EIGHT ohm speakers in parallel/series wiring can get you 8 ohms, no doubt. But there's no way four EIGHT ohm speakers can be wired to 4 ohms total. Likewise, andy FOUR speaker configuration that is 4 ohms total can't be reconfigured for an 8 ohm load.
     
  13. Take any 4 speakers with impedence X.


    Parallel: Cab ohms = X/4 (8 ohm cab=32 ohm spkrs)
    I----- X -----I
    I----- X -----I
    I----- X -----I
    I----- X -----I

    Series: Cab Ohms = X* 4: (8 ohm cab=2 ohm spkrs)
    ----- X -----+----- X -----+----- X -----+----- X -----

    Series-Parallel: Cab Ohms = X: (8 ohm cab=8 0hm spkrs)
    I----- X -----+----- X -----I
    I----- X -----+----- X -----I

    Checking above, you can only rewire your cab to change the impedance by a factor of 4. Depending on how its wired now your 8 ohm cab could maybe go to 2 ohms or 32 ohms, neither of which is particularly useful.

    Randy
     
  14. Selta

    Selta

    Feb 6, 2002
    Pacific Northwet
    Total fanboi of: Fractal Audio, AudiKinesis Cabs, Dingwall basses
    Rewiring your cab to buy those extra few watts wont buy you too much anyway, and is certainly not worth the hassel. Good luck though,

    Ray
     
  15. i just reread the diagram and you are indeed corect, i misread part of it

    and im still curious about the accugroove switch and "L" pads... does anyone have any details? legal details... the kind Mark wont have a hayday over people releasing :)
     
  16. I read on another forum that they think the drivers have dual voice coils with different impedences, that's the only thing I can think of that makes sense. Anything else (lpads, resistors, etc) to jimmy the impedence is useless, it just converts the extra power from running the amp at 4 ohms into heating the (lpads, resistors, etc). The speakers get no extra power out of the deal.

    Yes, you'd get more power out of your amp at 4 ohm loads. But in this case all that extra power produces waste heat, not acoustic energy.

    Yes, you'd get more miles out of your gas tank if it was 40 gallons instead of 20 gallons. But if you try to put 40 gallons in your 20 gallon tank, the 20 extra gallons that overflows onto the ground doesn't help move your car any farther.

    Same thing going on.

    Randy
     
  17. I tend to doubt it because however they do it, they've applied for a patent and I think it's a little late in the game to try and patent dual voice coil drivers.
     
  18. IvanMike

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

    Nov 10, 2002
    Middletown CT, USA
    ya know there's a great ohms faq thread linked in the faq sticky at the top of this forum.......... :cool: