8 and 16 ohm load in parallal?

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by ccoker, Dec 21, 2005.


  1. ccoker

    ccoker Supporting Member

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    I want to try a 3 speaker combo, have 3 8om speakers

    two 8s in series for 16

    and an 8ohm

    if I had these in parallel, it would be what? 12ohms?


    or I could wire the 8s in parallel for 4

    wire that in series with the 8 would yield what, 12 ohms?
    that seems obvious

    it's the 16 with the 8 in parallel that has me perplexed

    ideally a single 16 wire in parallel with the two 8s in series would have a net load of 8 ohms
     
  2. hasserl

    hasserl Member

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    Randall Aiken has some good info on adding components in series and parrallel on his site: http://aikenamps.com/ Look in the Tech Info / Introductory

    Hope that helps,
    Hasse
     
  3. bob-i

    bob-i Member

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    Let's see...

    1/16+1/8=
    1/16+2/8=3/16

    16/3=5.3333

    Your resulting load will be 5.3 ohms. You could use a 4 ohms tap for this.



    No... 1/8+1/8+1/8=3/8

    8/3=2.666... your load would be 2.666. Not a good idea unless you have a 2 ohm output like a Super Reverb or Tweed Bassman.

    No. 8+8+8=24 so that would be 24 ohms. Again not a great idea although with a 16 ohm tap that wouldn't be terrible.

    Yes, that's not easy to comprehend. The forumla is 1/R1+1/R2+1/R3....=1/Rt

    So add up 1/16+1/8 then invert the answer like I did above.

    It would seem that way, only with you have one speaker of higher impedance than another the result is that the lower impedance speakers receives more of the power. It can make the sound imbalanced and potentially overload the lower impedance speakers.

    I hope this helps.
    Bob
     
  4. baald

    baald Member

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    __/-8-\_8_
    ...=...12 ohms
    ..\-8-/

    ___/-8----8-\__
    ..=..5.3 ohms
    ...\----8---/




    make sense?
     
  5. ccoker

    ccoker Supporting Member

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    I looked all through there, couldn't find it
     
  6. Slick51

    Slick51 Colonel Curmudgeon Silver Supporting Member

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    Look again...

    Adding Components in Series and Parallel

    use the resistor formulae.

    Slick51
     
  7. ccoker

    ccoker Supporting Member

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    "or I could wire the 8s in parallel for 4 "

    I meant wire two of the 8s in parallel for a 4 ohm load

    and then wire in the other 8ohm speaker in series with the above for a comined 12 ohnm load
     
  8. bob-i

    bob-i Member

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    Yes, see the diagram that Baald posted, that should help you out.

    Personally I'd go with the 5.3ohm load solution I described above, and baald drew up in a nice diagram.

    ___/-8----8-\__..=..5.3 ohms
    ...\----8---/
     
  9. StompBoxBlues

    StompBoxBlues Member

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    I didn't see anyone mention it yet, but you MUST also consider the watts the speakers can handle.

    In the 5.3 ohm conficuration, The 16 side (the two 8's) together will draw a current that is half what the lone 8 ohm speaker draws!! That means whatever wattage the speakers are rated for, I think the lone 8 ohm will have to handle 2/3's of the amps output watts, while the other side only 1/3.
     
  10. ccoker

    ccoker Supporting Member

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    thanks guys..

    I have decided to not persue this any further

    got my existing cab (2x12) dialed in and it sounds perfect
     

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