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1000 watts into a 600 watt cab?

Discussion in 'Amps and Cabs [BG]' started by Ruptured, May 21, 2003.


  1. Ruptured

    Ruptured

    May 14, 2003
    Will 1000 watts into a 600 watt cab be safe as long as I don't crank the volume on the power amp too far??
    Do I just look out for the clip led to get a good safe level,or will the speakers overload way before then?

    Does a poweramp gradually put out more wattage as the volume is raised?


    thanks


    :cool:
     
  2. JMX

    JMX Vorsprung durch Technik

    Sep 4, 2000
    Cologne, Germany
    Usually it's safe to couple a cab with an amp with twice the power, e.g. a 1200W amp with your cab.

    It can be more risky to pair a small amp with a large cab than vice versa.

    Volume is "logarithmic".

    When you double the power of the amp, you get a boost of 3 dB, which is a noticeable increase, but not much.
    But if you want to get twice the (perceived) volume, you need a boost of 10 dB, for which you'd need 10 times the power.
     
  3. Bob Lee (QSC)

    Bob Lee (QSC) In case you missed it, I work for QSC Audio! Gold Supporting Member Commercial User

    Jul 3, 2001
    Costa Mesa, Calif.
    Technical Communications Developer, QSC Audio
    It's okay as long as you don't run your amp into any significant clipping, regardless of where you set the gain or volume control.

    The power (or wattage) that the amp puts out into the speaker depends on a couple things: the gain or volume setting and whatever signal you put into it. If you boost either one, you get more output, and thus more power. Neither one affects how much power the amp is ultimately capable of putting out, though. Most of the time you're running way below its maximum power anyway, which is good--otherwise you'd have a lot of clipping and distortion.
     
  4. I power a 400 watt cab with 700 watts. When it's really cranked the -10 LED comes on meaning I'm producing more than 80 watts but less than 700. As a rule unless you are really cranking, the average continous power you are feeding your speakers is no where near their rated continous capabilities. I think 1000 watts is a good match for a 600 watt cab.
     
  5. Ruptured

    Ruptured

    May 14, 2003
    Thanks guys


    So a QSC PLX 2402 run bridged would be a pretty good match for 2x 8 ohm 600 watt cabs run in parallel.2400 watts?

    Would I be straining the amp running it at it's biggest load all the time?
     
  6. tombowlus

    tombowlus If it sounds good, it is good Gold Supporting Member

    Apr 3, 2003
    North central Ohio
    Editor-in-Chief, Bass Gear Magazine
    I would think so. I run a similar load into my PLX 3002, and have not had any problems. I keep the gain on my PLX 3002 down to about 1/4 to 1/3 up, but I send a fairly hot (though by no means clipping) signal out of my preamp.

    Which begs a question, Bob. Would I be better off running the 3002 wide open, and using my Master gain on my preamp for control, or am I better off running a hotter signal into the amp and using the amp's controls? Or is there no difference?

    Later, Tom.
     
  7. Bob Lee (QSC)

    Bob Lee (QSC) In case you missed it, I work for QSC Audio! Gold Supporting Member Commercial User

    Jul 3, 2001
    Costa Mesa, Calif.
    Technical Communications Developer, QSC Audio
    There's not a big difference between them, but you can get better signal-to-noise if you back the amp gain(s) down somewhat and put a hotter signal through the system, from the preamp input gain (or even from the amp) on through (especially if you're running any effects or processing), as long as you don't get clipping at any point upstream from the amp. This is essentially what you're doing already, so keep on doing it as long as it works for you.
     
  8. tombowlus

    tombowlus If it sounds good, it is good Gold Supporting Member

    Apr 3, 2003
    North central Ohio
    Editor-in-Chief, Bass Gear Magazine
    Thanks, Bob! I have had good results running things this way, but wanted to pick your brain while I had the opportunity. Sorry to hijack the thread a bit, but I figured as long as we were on the topic...;)

    Tom.
     
  9. Ruptured

    Ruptured

    May 14, 2003
    No worries tom,it's all info I wanna know anyway:)


    I'd still like to know if running the PLX2402 bridged into 4 ohms (it's max power) constantly for a whole gig a week is going to put alot of stress on it or if it can handle it with ease?

    Thanks
     
  10. g4string

    g4string Supporting Member

    Sep 19, 2002
    Melissa, TX
    I run my PLX-1602 bridged into 2 Aggie GS112's which are rated at 300 watts each. I have had no problems with clipping or distortion. That is 1600 watts into 600 watt cab combo.
     
  11. I have heard that with the PLX it is best to run bridged with full tilt power and control signal(volume) with your preamp, thus giving more headroom..does this sound correct?
     
  12. tombowlus

    tombowlus If it sounds good, it is good Gold Supporting Member

    Apr 3, 2003
    North central Ohio
    Editor-in-Chief, Bass Gear Magazine
    According to Bob's reply to my post, above, this approach is not "best", but it should work fine, so long as you signal is not clipping anywhere along the line.

    Tom.
     
  13. Bob Lee (QSC)

    Bob Lee (QSC) In case you missed it, I work for QSC Audio! Gold Supporting Member Commercial User

    Jul 3, 2001
    Costa Mesa, Calif.
    Technical Communications Developer, QSC Audio


    Hi Rup,

    If you're not running the amp into significant clipping and you allow free flow of air into the back of the amp and out the front, you shouldn't have any problems.
     
  14. Bob Lee (QSC)

    Bob Lee (QSC) In case you missed it, I work for QSC Audio! Gold Supporting Member Commercial User

    Jul 3, 2001
    Costa Mesa, Calif.
    Technical Communications Developer, QSC Audio
    You mean full gain, not full power.

    As Tom said, it'll work fine. But it's best to use only as much gain in the power amp as you actually need, and get most of the gain you need up front in the preamp (and if possible, in the bass itself, if it's active).

    This is especially true if you're using any effects or processing, as the circuitry involved tends to be noisier than just straight gain or EQ circuitry (but not always). Having a sufficiently strong signal level (but not so strong that you clip anything) through these noisier parts and less gain later on in the signal chain helps reduce the hiss, buzz, etc. that you might hear in the loudspeaker.