Results 1 to 14 of 14

Thread: Series / Parallel switching for Speaker Cabinet

  1. #1
    Senior Member
    Join Date
    Mar 2010
    Posts
    68

    Default Series / Parallel switching for Speaker Cabinet

    Hi,

    I have a 2 x 12 speaker cab that is 16 ohms. It is two 8 ohm speakers in series. I use it with an Engl Ironball that has a 16 ohm output.

    I also want to use the cab with an amp that only has 4 and 8 ohm outputs. Putting the two 8 ohms in parallel will give me 4 ohms.

    So, I can re-wire for impedence matching for either amp, but not both.

    I've tried to sketch out the wiring for a switch to flip from one mode to the other.....can anyone confirm if this is correct? And does it matter whether the tip or ring of the speaker cable goes to positive on the speaker?

    Click image for larger version. 

Name:	Series Parallel speaker switch.JPG 
Views:	51 
Size:	50.0 KB 
ID:	99094

    Thanks,
    Andy

  2. #2
    Toneologist IM4Tone's Avatar
    Join Date
    Aug 2012
    Location
    State of Confusion
    Posts
    823

    Default Re: Series / Parallel switching for Speaker Cabinet

    This doesn't look right to me, but maybe I'm just not following your diagram correctly. HERE (7th from top) is a diagram for a DPDT switch to achieve 16 or 4 ohms (8 ohms isn't available with this configuration). Switch boxes are available for sale that are pre-wired.

    Regarding "And does it matter whether the tip or ring of the speaker cable goes to positive on the speaker?" .....If you are using this cab as a stand alone only, the importance is that both speakers are wired +/- the same to eliminate phase cancelling. If you plan on using this cab with another, tip is +, barrel is -. So, best to wire tip to +.

  3. #3
    Slutbucker Pimpologist ArtieToo's Avatar
    Join Date
    Mar 2004
    Location
    Jax, FL
    Age
    65
    Posts
    19,332

    Default Re: Series / Parallel switching for Speaker Cabinet

    The way to switch two speakers between series and parallel, is exactly the same as how to switch a humbucker between series & parallel. Use the Duncan diagram and pretend one speakers wire is +black and -white, and the other speaker is +red & -green. Use a slightly heavier duty switch, however.

    Name:  Spkr_Ser_Par.jpg
Views: 57
Size:  15.9 KB
    Last edited by ArtieToo; 06-17-2019 at 07:33 PM.

  4. #4
    Super Toneologist Dave Locher's Avatar
    Join Date
    Mar 2016
    Location
    Joplin, MO, smack dab in the middle of the U.S.
    Posts
    1,495

    Default Re: Series / Parallel switching for Speaker Cabinet

    What kind of switch should one use?

  5. #5
    Mojo's Minions
    Join Date
    Sep 2014
    Posts
    3,552

    Default Re: Series / Parallel switching for Speaker Cabinet

    Depending on the existing input type/size, this could be your easiest solution. It was virtually a drop in for one of my cabinets. If the input dish is smaller, the cabinet back can pretty easily be enlarged to accomodate.

    https://www.tubesandmore.com/product...lay-monostereo


    Last edited by Darg1911; 06-21-2019 at 04:37 AM.

  6. #6
    Toneologist IM4Tone's Avatar
    Join Date
    Aug 2012
    Location
    State of Confusion
    Posts
    823

    Default Re: Series / Parallel switching for Speaker Cabinet

    Quote Originally Posted by Darg1911 View Post
    Depending on the existing input type/size, this could be your easiest solution. It was virtually a drop in for one of my cabinets. If the input dish is smaller, the cabinet back can pretty easily be enlarged to accomodate.

    https://www.tubesandmore.com/product...lay-monostereo


    Quote Originally Posted by IM4Tone View Post
    This doesn't look right to me, but maybe I'm just not following your diagram correctly. HERE (7th from top) is a diagram for a DPDT switch to achieve 16 or 4 ohms (8 ohms isn't available with this configuration). Switch boxes are available for sale that are pre-wired.
    Exactly!

  7. #7
    Slutbucker Pimpologist ArtieToo's Avatar
    Join Date
    Mar 2004
    Location
    Jax, FL
    Age
    65
    Posts
    19,332

    Default Re: Series / Parallel switching for Speaker Cabinet

    Quote Originally Posted by Dave Locher View Post
    What kind of switch should one use?
    Simple DPDT on-on. But, obviously, rated for the power. A typical AC power switch would be more than sufficient.

  8. #8
    Toneologist regan's Avatar
    Join Date
    Sep 2015
    Posts
    826

    Default Re: Series / Parallel switching for Speaker Cabinet

    So long as the impedance of the cab is greater than the impedance of the amp you can use it.

    If you wire the cab at 16 ohms you can use it with 4,8, & 16 ohm amp outs

  9. #9
    Toneologist regan's Avatar
    Join Date
    Sep 2015
    Posts
    826

    Default Re: Series / Parallel switching for Speaker Cabinet

    Quote Originally Posted by Darg1911 View Post
    Depending on the existing input type/size, this could be your easiest solution. It was virtually a drop in for one of my cabinets. If the input dish is smaller, the cabinet back can pretty easily be enlarged to accomodate.

    https://www.tubesandmore.com/product...lay-monostereo


    this is just giving you one (2 speakers together) load at 16 ohms or 2 individual loads (2 speakers in stereo) at 8 ohms each

  10. #10
    Mojo's Minions devastone's Avatar
    Join Date
    Jun 2004
    Location
    Longmont, CO, USA
    Posts
    5,283

    Default Re: Series / Parallel switching for Speaker Cabinet

    Quote Originally Posted by regan View Post
    this is just giving you one (2 speakers together) load at 16 ohms or 2 individual loads (2 speakers in stereo) at 8 ohms each
    It's 4 ohms mono on the left top jack.

  11. #11
    Toneologist regan's Avatar
    Join Date
    Sep 2015
    Posts
    826

    Default Re: Series / Parallel switching for Speaker Cabinet

    Oh so it is,I missed that sorry

  12. #12
    of the Forum PFDarkside's Avatar
    Join Date
    Jul 2005
    Location
    Somewhere around... Chicago!
    Age
    39
    Posts
    16,825

    Default Re: Series / Parallel switching for Speaker Cabinet

    Quote Originally Posted by regan View Post
    So long as the impedance of the cab is greater than the impedance of the amp you can use it.

    If you wire the cab at 16 ohms you can use it with 4,8, & 16 ohm amp outs
    This is only true with solid state power amps.
    Oh no.....


    Oh Yeah!

  13. #13
    Toneologist regan's Avatar
    Join Date
    Sep 2015
    Posts
    826

    Default Re: Series / Parallel switching for Speaker Cabinet

    Quote Originally Posted by PFDarkside View Post
    This is only true with solid state power amps.
    Nope, It's quite OK

    https://mesa-boogie.imgix.net/media/...d%20Hookup.pdf

  14. #14
    of the Forum PFDarkside's Avatar
    Join Date
    Jul 2005
    Location
    Somewhere around... Chicago!
    Age
    39
    Posts
    16,825

    Default Re: Series / Parallel switching for Speaker Cabinet

    Quote Originally Posted by regan View Post
    You’ll notice in the documentation that it states at maximum a doubling of load impedance is ok. (4 ohm amp and 16 ohm speaker is not OK). For solid state this is ok.

    Also, I’d trust this advice for manufacturers that explicitly mention you can mismatch impedance. Not all amps are built with the robustness of Mesa Boogies.
    Oh no.....


    Oh Yeah!

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •