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How do you run 2 , 2x10s (at 8 ohms each) at 4 ohms?

Discussion in 'Amps and Cabs [BG]' started by KlarkKent, Jul 14, 2002.


  1. KlarkKent

    KlarkKent

    Dec 17, 2001
    Los Angeles
    Here's my problem a Goliath 4x10 at 4ohms would be perfect for me...problem is I can't afford a new one. Since they just came out with the 4 ohm version, there are hardly any out there used. However, there are tons of Goliath III Jr's out there used.


    So....

    I have a carvin DCM 1000 power amp, (1000 bridged @ 4ohms, 350/350 @ 8 ohms.) If I recall theres a way to run , (with cables) 2, 2x10s so they turn out to be 4ohms? In other words, I don't want to run a Goliath III jr. 2x10 out of each side of my power amp, it would not leave me with much headroom. But, if I ran a speakon out of my power amp into one of the Goliath Jr's and then ran a cable from that one to the second Goliath, would'nt I have 1000 watts at 4 ohms into two cabs each rated at 350 Watts RMS for a total , (more or less) of 700 watts?

    I am smoking crack or could this work?


    klark kent
     
  2. Knack

    Knack

    Mar 25, 2002
    New York City
    Yes, that is how to do it.
     
  3. JMX

    JMX Vorsprung durch Technik

    Sep 4, 2000
    Cologne, Germany
    [EDIT] I initially misread your post. He's right.
     
  4. KlarkKent

    KlarkKent

    Dec 17, 2001
    Los Angeles
    Let me be more specific...my power amp puts out 350 a side at 4ohms and 225 a side at 8 ohms, in bridged mode 1000 at 4ohms, 700 at 8 ohms.

    If I ran 2 2x10's (goliath III Jr. 350 rms @ 8ohms) in PARALLEL would that not be the same as having a 4x10 at 4ohms? Each 2x10 would be running at full power (350RMS) and my power amp would running at full power, 1000 watts, that would leave plenty of head room right?

    Here's the real question, ..is there any difference between the previously mentioned set up, (PARALLEL),

    and......

    having a goliath III Jr. running on one channel of my power amp, and the other goliath III Jr. running out of the other channel.


    The latter does not to me sound ideal because there is no headroom. Each channel is 250 watts @ 8ohms, and the amps are rated 350 RMS.
     
  5. If you did this, each cabinet would be getting 500 watts (maximum!), not 350. Where did you think that other 300 watts from the amp would be going, if it's putting out 1000 watts?

    Yes, of course there is. In the first case, you're running the amp in "bridged mono" mode--that is, you're combining the output from the two halves of the power amp into one output, then running that into both cabinets, which are connected in parallel. The cabs in parallel have a combined impedence of 4 ohms, or two ohms per each amp channel.

    In the second case, you're running a stereo setup, with each power amp channel having one cabinet, for an impedence of 8 ohms per channel.

    Mike
     
  6. KlarkKent

    KlarkKent

    Dec 17, 2001
    Los Angeles
    Ok ..so mike whats your opinion is this a good idea or a bad one? You said each cab would be getting 500 watts that sound good, plenty of head room for each cab.
     
  7. I don't se any problem with the idea, really--the 350 watt rating on the cabs is (usually) for "continuous" power, and cabs can oftten handle peaks of 2-3 times their rated power. You will be running the amp a bit harder, which may shorten it's life in the long run, but that hasn't stopped me with my Mackie power amp.

    Mike