measuring wattage..

[Mr Bojangles 10+ year member]

How do you go about measuring the exact wattage your amp is putting out when turned up? Is there even a way?

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[Mr Bojangles 10+ year member]

no one knows??

 

[budahbuddy803 10+ year member]

DMM and a formula will get how many watts your amp is putting out i think

 

[Mr Bojangles 10+ year member]

where do i find a dmm? Kind of like a volt ohm meter?

 

[jdawg 5,000+ posts]

digital multi meter, Yea a volt ohm meter. You can get them for like $10 at harbor freight for cheap ones. Best way to test you amp though is take it to a shop, have them hook up power supplies and bench test it

 

[Mr Bojangles 10+ year member]

i have a volt ohm meter.. So what is the formula?

 

[zero hero 10+ year member]

Digital Multi Meter is a DMM

How ever there is a true way to do it but its not cheap.You need a dummy load that will handle the AC volts your amp puts out.Wire to your amp with a DMM in line and a O-scope to set it first I forgot. Read your AC volts and convert them to RMS.Unless you have a True RMS meter

If you use a speaker and not a load you get off readings but they are a guess

 

[Mr Bojangles 10+ year member]

so with the DMM and a formula i can do it right? What is the formula for converting ac volts to rms?

 

[jdawg 5,000+ posts]

yea but it wont be acurate. See you speaker resistance changes at different frequencies, so the AC volts would be all over the place. Has alot to do with box design. A speaker is not a constant load. I dont know the formula but when you start getting into this you have to have basic knowledge of ac volts, dc volts, resistance, voltage, amperage, etc And know how they all are different and can effect each other

 

[jdawg 5,000+ posts]

came up with this http://www.installer.com/tech/watts.html

 

[jdawg 5,000+ posts]

voltage times voltage divided by impedance. For instance, if your voltmeter says 10 volts and you know your speaker to be 4 ohms then simply calculate 10 volts times 10 volts which is 100, then divide by the impedance 4.. 25watts… Very simple!

 

[qtipextra 5,000+ posts]

Although jdawg is trying, he is missing alot.

In order to get an acurate reading, you need a true RMS volt meter (which are not cheap) and a true RMS amperage meter. You hook them both up, and you get readings, and you multiply those readings together. That is the TRUE RMS output at a given time with your system.

When jdawg suggested bench testing, that is not true. That is to find out the peak RMS power of the amp with out clipping. It is not used to find out how much actual power, because of the impedence rises of the box, and heat differences, and a lot of other varibles.

 

[jdawg 5,000+ posts]

yea what he said, I am no means the expert lol

 

[qtipextra 5,000+ posts]

yea what he said, I am no means the expert lol

I ment no dis-respect. I give you mad props for trying to help. If only we had more people like you, people that actually tried to help instead of just trying to raise their post count.

 

[luvinthebass 5,000+ posts]

if you go into the deep details it'll give ya nothin but a headache and make ya think that your amp is weak when it says "1000 rms"