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Question about watts

Discussion in 'Amps and Cabs [BG]' started by lfmn16, Nov 29, 2016.


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  1. lfmn16

    lfmn16 Supporting Member

    Sep 21, 2011
    charles town, wv
    I know this has probably been answered multiple times, but I performed a search and couldn't find the answer. I am getting two cabinets - Ampeg PF-210 HE and Ampeg PF-115 HE (please don't turn this into a mixing cabinets thread). They are 450 watts each. Of course always using my ears to make sure I don't overload them, in theory, they should handle 900 watts combined, right? I'm actually planning on getting an Ampeg PF-800.

    Thanks.
     
  2. They will handle about 500-600 watts safely.
     
    Cirk likes this.
  3. To answer the question in a technically correct manner, yes.
    The power rating of two equally rated cabs doubles the rating of that of the single cab.
    That being said, it is possible to damage speakers with an amp of less power than the combined ratings of the cabs.
    Hence the cautionary statement from CL400Peavey.
     
  4. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    It depends... are they both 8 ohm cabinets?
     
  5. Depends also on what you mean by handle. You control how much power goes into the cabs.

    It's probably a good thing having a ''too big'' amp. You know you cannot expect to crank it so you listen. The problem comes when fools expect a 500w amp can be cranked into 500w worth of cabs without listening.

    It's not even that easy to listen carefully to 500w worth of bass with accompanying drums and guitars. So mind how you go.
     
  6. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    You would be amazed at how efficiently "fools" can destroy a speak, or multiple speakers... and not just one time mind you.

    (* note that fools are not really fools, but don't understand what they are doing, or have been given bad advice (maybe on the internet even) without knowing that it's bad or why it's bad)
     
    monsterthompson and blindrabbit like this.
  7. seanm

    seanm I'd kill for a Nobel Peace Prize! Supporting Member

    Feb 19, 2004
    Ottawa, Canada
    I have a 500W combo amp with a 250W speaker. I have used it quite often in that configuration with no problems.

    When I am in a louder band, I need an extension cab. Once in a while I have noticed that the rig sounds distorted. This *always* means I forgot to plug in the second cab and am pushing the first cab too hard.

    So pay attention to your cabs, and don't worry about it :D
     
  8. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    The problem is that sometimes it's hard to tell on stage, in a band mix with drums and gtr.

    Another challenge is with some speaker designs that overload gracefully and musically, it's quite possible not to notice, or actually gravitate towards this tone.
     
  9. lfmn16

    lfmn16 Supporting Member

    Sep 21, 2011
    charles town, wv
    excellent question, yes they are.
     
  10. lfmn16

    lfmn16 Supporting Member

    Sep 21, 2011
    charles town, wv
    This isn't a trick question. I'm just trying to confirm that if you have two cabinets rated for 450 watts, then combined that are rated for 900 watts. I've been playing long enough to know that you ALWAYS need to use common sense and your ears.

    Thanks to everyone that chimed in.
     
  11. See my post #3.
     
    Ant Illington likes this.
  12. lfmn16

    lfmn16 Supporting Member

    Sep 21, 2011
    charles town, wv
    Why, did you change it? :D

    I was responding to the people who seem to think I'm asking something other than the simple, straight forward question that you answered.
     
    Old Garage-Bander likes this.
  13. I have (2) Ampeg 15" 8 ohm cabs... 200 watts each. I wanted to make sure my SVT would not over power them, so I emailed Ampeg. The response I got back was that the 2 could handle 400 watts, so not a problem. That's consistent with the doubling opinions given here. You can always email Ampeg, just for the extra sanity check.
     
  14. lfmn16

    lfmn16 Supporting Member

    Sep 21, 2011
    charles town, wv
    Thanks. This is more for my edification than anything else. I thought that if you had two cabinets with equal watts, you add them to get the total, but wanted to make sure. I don't play that loudly anyway.
     
  15. That isnt what I said at all. The real world mechanical power handling of those two cabs together is 500-600 watts. Past that, they are not going to do anything with the additional power, but fart out, and potentially deteriorate.

    500-600 watts will drive those cabs to their limits.
     
  16. mikeyjm2

    mikeyjm2 Keepin' it simple.

    Dec 31, 2014
    Houston, TX
    As long as they're both 8 ohm (which you say they are) the power will be equal to both, but in the case where you had one 4 and one 8 ohm the 4 ohm cab would be getting more of the power than the 8 ohm would. Watts = Volts^2 / Ohms is the simple way to look at it math-wise.
     
  17. wcriley

    wcriley

    Apr 5, 2010
    Western PA
    And it's even harder to tell if the distortion is caused by overdriving the amp, overdriving the speakers or having a low battery in the instrument. (Unless you're smacking the backplate, which is a very distinctive noise...ask me how I know.)
     
    agedhorse likes this.
  18. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    Or using a distortion pedal.
     
  19. Plucky The Bassist

    Plucky The Bassist ZOMG! I'm back from the dead!

    Jul 30, 2010
    Houston, TX
    Aww man! Stopped me before I was even in the door!!! :(

    45465376.jpg
     
    BadExample and lfmn16 like this.
  20. MDBass

    MDBass Supporting Member

    Nov 7, 2012
    Los Angeles, CA
    Endorsing Artist: Dingwall-Fender-Bergantino-Dunlop-Tech 21-Darkglass-Nordstrand
    Two important things:

    1. The wattage rating of a cab is only their thermal rating, meaning the amount of wattage the drivers can take before literally starting to burn. You can still easily run into over-excursion and mechanical failure at "safe" wattage levels.

    2. The wattage rating of an amplifier is only the maximum wattage it's capable of producing, and it will only produce that number if you turn the master up far enough. At lower volume levels the wattage produced is also lower, but remember to keep in mind point #1 regarding "safe" wattage.

    That pairing is totally fine, just use your ears and be careful with the master :thumbsup:
     
    lfmn16 and SanDiegoHarry like 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.

     
    May 14, 2021

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