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200 Watts Rating, 35 Watts Draw?

Discussion in 'Amps and Cabs [BG]' started by MuffledBoomy, Apr 17, 2018.


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  1. MuffledBoomy

    MuffledBoomy

    Apr 19, 2017
    Tulsa
    None
    I just purchased my first Class D amp and got to say I am pleased so far. But how does an amp rated 200 Watts output have a rated power consumption of 30 Watts? (Info source is the labeling on the amp.)
    Anybody know anything about this?
     
  2. Stumbo

    Stumbo Guest

    Feb 11, 2008
    Which amp?
     
  3. 30 watts at 120 volts A.C. input. Assuming U.S. (Even OK :smug:).
    200 watts at some lower output voltage.
     
  4. 10:1 it's an Elf.
     
    fcleff, Aqualung60 and svtb15 like this.
  5. Bflat

    Bflat

    Feb 5, 2008
    duty cycle maybe???? or sales bull
     
  6. BadExample

    BadExample

    Jan 21, 2016
    Injiana
    Yes. It's an average usage under normal conditions. Nothing to worry about, just a regulatory rating.
     
    Bflat likes this.
  7. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    Regulatory agencies determine this based on 1/8-rated power duty cycle for safety and EMC agency testing. It's a global thing.

    Take rated audio power divided by efficiency then multiply by 1/8 duty cycle and you should be close to the minimum rating for average power consumption.

    In this case, 200w/85% = 230W

    230W x 1/8 = 29W

    Nothing marketing, nothing nefarious, just simple math and regulations.
     
    Kro, Al Kraft, Coolhandjjl and 6 others like this.
  8. Rick James

    Rick James Inactive

    Feb 24, 2007
    New Jersey
    According to the manual average draw is 30w, maximum is 240w. 30w would be the 1/8 power figure. Most pro-sound power amps are rated for current draw at 1/8 power, because if you run at much more than that you don't have enough headroom. Why they show power draw instead of current draw is unusual, but the two are linear, so it's a valid number.
     
    BadExample likes this.
  9. MuffledBoomy

    MuffledBoomy

    Apr 19, 2017
    Tulsa
    None
    Oh, the number is 1/8 power? Like an average between resting and outputtng at good headroom levels?
    Thanks for your help. And yes Elf, and I like it so far.
     
    BadExample likes this.
  10. Rick James

    Rick James Inactive

    Feb 24, 2007
    New Jersey
    More like the actual power at average playing levels. You use a lot less power than you think you do.
     
    BadExample likes this.
  11. How many watts of droning sines can you get out of it?
     
  12. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    These days, it's becoming universal to use power rather than current for the ratings because more and more gear is capable of operating from 100-240V and using power GREATLY simplifies managing the back panel graphics.
     
  13. Bflat

    Bflat

    Feb 5, 2008
    200watts until the fuse blows since it wasn't sized for that......its the new math:laugh::laugh::laugh:
     
    Last edited: Apr 18, 2018
  14. BadExample

    BadExample

    Jan 21, 2016
    Injiana
    No one likes a cooked elf. Most amps get warm if you run a sine wave too long at low freq.
     
  15. AlexanderB

    AlexanderB

    Feb 25, 2007
    Sweden
    Well, it is NOT equal to 230 W in this case or any other case, as it is not 15% more... Actually, 200 W/0,85 is a bit over 235 W... Changes nothing in this context, but the glaring "=" looks just... wrong...

    But sure, there is no magic numbers in play. It can be a bit frustrating to see how techno-phobic people inte MI fail over and over to grasp the concepts of energy storage, duty cycle, phase angle etc. A 5 kW amp hooked up to a 230 V 10A wall outlet is no perpetum mobile, it will only re-package energy that is available from the power lines.
     
    Last edited: Apr 18, 2018
  16. BadExample

    BadExample

    Jan 21, 2016
    Injiana
    Andy or Rick would know for sure, bit I think 1/8 of max. is the minimum they can claim for audio.

    My network stuff at work is labeled at some insane max. power. That would probably be valid if all interfaces were in use, CPU and memory maxed from activity of an overloaded network, and PoE was used to it maximum available. I had to measure the reality, and got between .5 and 1 amp. Called it 2 Amps for power planning. The UPS/PDUs (fancy power strips) indicate my measurements were correct during peak netwok activity.

    If our amps were rated at max. power at the cord, the big hitters would need some special power arrangements. The gear in my datacenter is running off of two 30 Amp 220 VAC dedicated circuits. We run at less than half that.
     
    Last edited: Apr 18, 2018
    mikewalker and Bflat like this.
  17. micguy

    micguy

    May 17, 2011
    Yes, it's a ratings thing, but part of me imagines there's a small nuclear reactor on board to supply the power it doesn't get from the wall - just like our space probes that go to the outer solar system. If the amp is warm when it's not plugged in, I'd pass.
     
    mikewalker and 2tonic like this.
  18. BadExample

    BadExample

    Jan 21, 2016
    Injiana
    I think it was Venus or Saturn we nuked. If little green men live in there, under ground, or under the gasses, I'll bet they're pissed.
     
  19. micguy

    micguy

    May 17, 2011
    If little green men live on Saturn, they're likely swimming in liquid hydrogen (our present best guess is there is no "ground"/solid surface). A few pellets of Plutonium dispersed over their ocean probably won't wreck their day - I'd guess they're a pretty tough lot.
     
    fcleff, BadExample and agedhorse like this.
  20. 2tonic

    2tonic

    Dec 22, 2015
    You, more than anyone, would know!!! :D

    Frankly, I don't mind you all that much! :woot:
     
    BadExample likes this.
  21. Primary

    Primary TB Assistant

    Here are some related products that TB members are talking about. Clicking on a product will take you to TB’s partner, Primary, where you can find links to TB discussions about these products.

     
    Apr 23, 2021

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