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how do I power 3, 4ohm cabs?

Discussion in 'Amps and Cabs [BG]' started by LarryO, May 14, 2006.


  1. LarryO

    LarryO

    Apr 4, 2004
    What would be needed? a "tricked out" chord? Biamp capability, stereo rig? Ideally id like to run the same signal to all 3 cabs. They are all 4ohms each. Any advice?
     
  2. Ryan L.

    Ryan L. Moderator Staff Member Supporting Member

    Aug 7, 2000
    West Fargo, ND
    What head are you going to be using??
     
  3. Eric Cioe

    Eric Cioe

    Jun 4, 2001
    Missoula, MT
    What amp are you running? And what cabinets are they?

    If your amp can run at 2.67 ohms, you could run a series cable between two of the cabinets, bringing their collective impedence to 8 ohms rather than 2, and then just run the other cabinet in parallel with that for a 2.67 total ohm load.

    The problem with this setup is that the one cabinet run without the series cable would be a whole lot louded than the other two.

    You might run one cabinet off of yoru current head and then two off of each side of a stereo power amp. Or, if the stereo power amp has 2 ohm per side capabilities, you could run two cabinets from one side of the amp (2 ohms) and one from the other (4 ohms). You could balance the levels with the volume controls.
     
  4. acexxxoasis

    acexxxoasis

    Apr 12, 2005
    why 3 cabs? you could try rewiring one of the cabs maybe?
     
  5. LucyQuack.
     
  6. The 0x

    The 0x

    Aug 24, 2003
    Timonium, MD
    You could get a Fender 400PS. They were designed to run with 3 4-ohm cabs.
     
  7. theshadow2001

    theshadow2001

    Jun 17, 2004
    Ireland
    I would agree that the best way to do this is with a stereo power amp powering two cabs with your head powering the the third. Or two in series on one channel and the third on the other.

    With your setup I don't think theres anyway to rewire to get them to run with your head and en up with a 4 or 8 ohm load
     
  8. theshadow2001

    theshadow2001

    Jun 17, 2004
    Ireland
    :confused:

    Heh heh its david bowies dog. but even so...:confused:
     
  9. BillyB_from_LZ

    BillyB_from_LZ Supporting Member

    Sep 7, 2000
    Chicago
    LarryO...assuming you're want to use the three cabinets and the amp in your profile...you could add a poweramp to the rig and drive it with a line out from the Peavey head.

    Aother option would be to make/buy a special speaker cable to connect two of your cabinets in series...the resulting load (when the series connected cabinets are connected in parallel with the third) would be 2.7 ohms. While the two series connected cabinets would each get half as much power as the third, the volume difference (assuming identical sensivity) would be just 3dB and perhaps barely noticable.
     
  10. ibz

    ibz

    Apr 14, 2005
    Columbus, OH
    Versatile solution:
    Two power amps

    Power amp 1 having the requirement of being able to run at 2ohms.

    Power amp 2 being able to run at 4 ohms.

    Find a good splitter for your preamp output that has good signal strength at both ends.
     
  11. LarryO

    LarryO

    Apr 4, 2004
    sorry, I should have specified.....YES i want to use the 3 cabs listed in my profile. No, not the amp listed in my profile. I was looking into using all 3 cabs with a pre-power-power setup but wondering if anypower amps can run 3 loads simutaneously or if 2 power amps is the way to go. I wouldn't be using all 3 cabs together often so the fewer pieces I have to buy the better.
    I am already in deep doodoo with the wife (an ampeg
    b500dr on the way, bidding on a Mesa 400 and looking at another PV 210 tvx) She's not oo happy....LOL
     
  12. ibz

    ibz

    Apr 14, 2005
    Columbus, OH
    Side comment, but those 210 tvx are pretty good cabs for how cheap I've seen them being sold. And they have some pretty good low end too.
     
  13. LarryO

    LarryO

    Apr 4, 2004
    Yes The 210TVX cabs are good, so are the 115BVX cabs. The only downside to these cabs are the weight.
     
  14. todd 4ta

    todd 4ta

    Apr 3, 2003
    Indiana
    I would try to keep the power > cabinet combination consistent for all 3 cabs, otherwise you'll have a difficult time getting it balanced. Of course, your three cabinets aren't identical so the 2x10 may require a slightly different output level to be balanced with the two 1x15 cabs.

    My recommendation would be to use two identical power amps (your choice) and run one channel of each amp to one cab each (at a 4 ohm load). You will have one unused channel (a backup in case you need to add a 4th cab ?!)

    Some preamps have two preamp outputs, so you could run 1 to each of the power amps. If the preamp you choose only has one output, you would have to go with a good quality Y-cable. Some amps have the ability to send a slave output signal to a second amp when running in bridged or parallel mode (I think).

    I'm pretty sure if you go with a pre/power amp for 2 cabs and a amp head for the 3rd, you'll have balancing issues. The second best option would be to use 2 power amps, one using 2 channels and the 2nd in bridged mode to the 3rd cab. You could get by with a slightly less powerful amp for the second power amp (say a PLX-3602 for amp 1 and a PLX-1602 for amp 2 - for one example).
     
  15. Munjibunga

    Munjibunga Total Hyper-Elite Member Gold Supporting Member

    May 6, 2000
    San Diego (when not at Groom Lake)
    Independent Contractor to Bass San Diego
    Seems to me Carvin makes a couple power amps with four separate outputs, one with 1,200 watts (300 watts per channel) and one with 4,000 watts (1,000 watts per channel).

    Carvin DCM1204

    Carvin DCM4000

    [​IMG]

    [​IMG]
     
  16. Eric Cioe

    Eric Cioe

    Jun 4, 2001
    Missoula, MT
    Chances are the power amp you will be running allows 2 ohms per side. Simply plug your 1x15s (you have 2, correct?) into one side of the power amp, and run the 2x10 off of the other. Set levels to balance, and you're good to go. No need for two power amps here.
     

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