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impedance question-not that i would but i could

Discussion in 'Amps and Cabs [BG]' started by sirdugh, Jun 21, 2008.

  1. Jun 21, 2008 #1
    sirdugh

    sirdugh

    Dec 22, 2007
    columbia, mo
    so I have an svt2. Currently, I have 3 ampeg cabinets. 210(8 ohm), 115(8ohm), and 410hlf(4ohms).

    Couldn't I connect the 15 and the 10's to one speaker jack for a load of 4 ohms and connect the 410 to the other speaker jack? Wouldn't this result in an overall load of 2 ohms?

    I have no idea why I would ever need this setup but I just want to know. On the other hand, maybe I'll just sell them all and buy a berg cab.
     
  2. Jun 22, 2008 #2
    bongomania

    bongomania Supporting Member Commercial User

    Oct 17, 2005
    PDX, OR
    owner, OVNIFX and OVNILabs
    Yep, sounds right to me.
     
  3. Jun 22, 2008 #3
    JimmyM

    JimmyM Supporting Member

    Apr 11, 2005
    Apopka, FL
    Endorsing: Yamaha, Ampeg, Line 6, EMG
    Dude, you know you have to set it up at least once!
     
  4. Jun 22, 2008 #4
    Willem

    Willem

    Dec 26, 2005
    Belgium
    Would work perfect and you NEED to do that!
     
  5. Jun 22, 2008 #5
    jetofuj

    jetofuj

    Jun 16, 2008
    PL
    If you connect 8ohm cab to another 8ohm cab and then to speaker jack, you won't get 4ohms but 16ohms. There is a difference between series and parallel connections.

    Series:
    i=i1+i2+...

    Parallel:
    i=1/i1+1/i2+...

    "i" is a total impedance, "i1" and "i2", etc. are cabs impedance.

    am I thinking right?
     
  6. Jun 22, 2008 #6
    Jaco who?

    Jaco who?

    May 20, 2008
    You got the series parallel concept down, but probably 98% of speaker cabs piggy back connections are parallel, not series.
     
  7. Jun 22, 2008 #7
    bongomania

    bongomania Supporting Member Commercial User

    Oct 17, 2005
    PDX, OR
    owner, OVNIFX and OVNILabs
    Connecting the two 8 ohm cabs through their paired inputs would be a parallel connection in the vast majority of cases, not a series connection.
     
  8. Jun 22, 2008 #8
    MuzikMan

    MuzikMan

    Feb 21, 2004
    Bristol, Connecticut, USA
    I've never seen a commercially built amp or cab with a series connection. They're parallel. Hence, 2 ohm load in your case.

    BTW it really doesn't matter exactly where the piggy back is located. For instance you could connect your 4 ohm and 8 ohm cab together, and use the other jack for the other 8 ohm cab. The end result would be the same.
     
  9. Jun 22, 2008 #9
    JimmyM

    JimmyM Supporting Member

    Apr 11, 2005
    Apopka, FL
    Endorsing: Yamaha, Ampeg, Line 6, EMG
    Nemesis does it. The old 210 combo was wired for 4 ohms to get 200w output, and if you hooked up an ext. cab, it dropped to 8 ohms and cut the power.
     
  10. Jun 22, 2008 #10
    projectMalamute

    projectMalamute

    Jan 9, 2008
    Westfield, MA, USA
    If you connect the cabs in this manner you are connecting them in parallel. This misconception that daisy chaining cabinets together is wiring them in series seems to be rampant around here. It's not.

    Also, your second equation is wrong, it should read 1/i = 1/i1 + 1/i2 + ...
     
  11. Jun 22, 2008 #11
    Rick Auricchio

    Rick Auricchio Registered Bass Offender Supporting Member

    Nov 27, 2007
    Cambria, CA (Central Coast)
    But not on unpowered cabs; just on some combo heads.

    For the OP: Remember when connecting multiple cabinets that the total power from the amp will be distributed among the cabinets.

    4-ohm cab: 1/2 the total power
    8-ohm cab: 1/4 the total power
    8-ohm cab: 1/4 the total power

    Be careful not to fry the 4-ohm cab.
     
  12. Jun 22, 2008 #12
    Psycho Bass Guy

    Psycho Bass Guy Inactive

    Mar 9, 2000
    The hills of Tennessee
    150 watts is not going to hurt that 410HLF.