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check amp watts

Printed From: the12volt.com
Forum Name: General Discussion
Forum Discription: General Mobile Electronics Questions and Answers
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=59125
Printed Date: May 06, 2024 at 5:39 PM


Topic: check amp watts

Posted By: Legrones
Subject: check amp watts
Date Posted: July 09, 2005 at 4:31 PM

does any one know if u can check a amp to see how many watts is cummong out with a DMM ?and if so how ?

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Dale / Cory



Replies:

Posted By: 349517
Date Posted: July 09, 2005 at 5:55 PM
not 100% positive but i do not believe so. I thik you need a ammeter for that.




Posted By: 349517
Date Posted: July 09, 2005 at 5:57 PM

349517 wrote:

not 100% positive but i do not believe so. I thik you need a ammeter for that.

although, using ohms you might be able to figure it out with one of these 3 equations

I x E   

Isquared x R

Esquared / R





Posted By: genehewett
Date Posted: September 15, 2005 at 12:44 AM

There are a lot of factors that determine the amount of power an amp is putting out at a given time. There are expensive testing equipment that can test max, or RMS output of an amp. But remember you may own a 1000watt amp and it during it entire life not produce 1000watts. This could go on for ever so here is a good rule to go by.

Add all fuses in the side of the amp togather. Multiply this number by 12.5 we all know when you jamin your system voltage is not 14.5 so dont use it. This number would be the amps max output if it were 100% efficient. Sorry its not so divide that by 50%. This is also considering other factors. This is close to the amps RMS power (useable power).





Posted By: stevdart
Date Posted: September 16, 2005 at 11:07 PM

Legrones wrote:

does any one know if u can check a amp to see how many watts is cummong out with a DMM ?and if so how ?

What you would measure would be voltage output.  If you set up your system and set head unit output and gains correctly using sine wave test tones recorded at 0 db....and are confident that the output is 100% clean (no clipping).....you can remove the speaker wires from the amplifer to test.  Probe the meter leads onto the amp's speaker outputs while the system is at full level and while playing the test tone(s) you used when you set it up.  The meter should be set to AC volts.  You'll get a continuous reading of voltage on each set of terminals that you had loads attached to.

You have to then use Ohm's Law to figure out power (watts).  Use a formula for finding power...in this case you know these two things:  the impedance load that you have attached to the set of terminals, and the voltage that you have just measured.  Look at the possible formula combinations HERE.  You would choose P = E^2 / R (because of your two known factors) .  Square the voltage reading (E times E) and divide that number by the impedance load (R) attached to that set of terminals.  Do the math and you will find the watts.



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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.





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