Check Actual Ouput Of An Amplifier?

[Aukland]

I was wondering if there was a way to check actual output of an amplifier. My buddy has a RF T20001bd he got used and just wanted to know actual RMS output, is there a way to do this??

[ISO]

Go to realm of excursion and type this heading in the search engine over there ( How to measure Imp/Box Rise? )

I can't make a direct link to it unfortunetly and I'm not going to retype everything.

But Look for ISO and you will find your answers.

No need to go to ROE I have transfered all my info to this thread

[ALPINE408]

Its called a clamp metter

[ISO]

Its called a clamp metter

You can't just use a calmp meter. You need a clamp meter and a DMM and need to know the formulas to figure this out.

[ISO]

HERE I WILL COPY AND PASTE THE INFO.

This is what we uesd to do for our SPL vehicles.

The first thing we did was use an O-scope to set all of the gains.

Unforfunetly you can't do that unless you have an O-scope.

So just set your stuff up the best you can by ear.

Next take your DMM hook the positive up to the positive speaker wire at the amp so your positive speaker wire and positive wire from the DMM are connected to the positive speaker terminal on the amp.

Now do that with the negative also. Do the negative the same way you just did the positives.

and set the DMM to AC voltage.

Now take your clamp meter and clamp that only around the positive speaker wire comming out of the amp.

Set the clamp meter to AC amperage.

Now the install part is done.

Next you need a test tone disc.

Set the volume on the head unit to were you feel everything is as loud as you think it shoud be.

Or if you have an O-scope set your volume rite at clipping. Just a hair less so your not running a clipped signal and remember that volume number becuase you will need to do all your testing at those same settings to get an accurette Idea of whats going on.

Now with the DMM set to ac voltage and the clamp meter set to ac amperage take the test tone disc and find a frequency to start with, burp your system and write down the results from the DMM and clamp meter.

Both those numbers need to be writen down at the same time or you won't get propper results.

then go up 5 hertz burp again and write it down.

then go up another 5 hertz and do it again.

Example:

start at 30 hertz burp then 35 burp 40 burp and keep doing that until you have gotten to 80 hertz.

Now the physical work is done.

Alright now you need a calculator and a place to sit down and relax and you want to well im going to write it for you the way I've got it wrote down in my notes.

AC voltage from the speaker outputs divided by the amp draw on the positive wire from the amp.

That will give you your impedance at each frequency.

Heres some thing extra for you do you really want to know how much power your amp is really making do this.

Multiply the AC voltage by its self then divide that number by the ohm loads you just came up with.

thats a heck of alot more realistic than just use 4 ohms or 2 ohms becuase you just did the work to find out what your amp is really seeing. so the wattages you come up with are alot more realistic.

I'm going to post this then I'll have another post for you that shows you how I set up my paper.

After my next post if you don't get it PM me and I'll try to help but I would like to have any question you ask to be posted in this thread so it can help others.

Edit 02/09/2010:

To have fun with and to help, Ohm's Law/Watt's Law Calculator:

http://www.crownaudio.com/apps_htm/designtools/ohms-law.htm

[ISO]

Hers an example of a kicker ZR360 running to 2 10 inch solo L7 tens with a nominal 2 ohm load.

Volume-----Frequency-----AC voltage----AC amperage-----ohms------watts

31 --------------20--------- ----41.4------------10.7 -----------3.87------- 443

31---------------25--------------44.1-------------9.6------------4.6---------423

31---------------30--------------44.3-------------9.7------------4.56--------430

31---------------33--------------48.3-------------7.4------------6.53--------357

31---------------40--------------48.9-------------3.75---------13.04--------183

31---------------50--------------38.4-------------3.15---------12.19--------121

31---------------60--------------42.9-------------9.22----------4.65---------396

31---------------70--------------33.5-------------9.16----------3.66---------306

Do you get the idea.

Do you see that even though I am running a nominal 2 ohm load I never hit 2 ohms

but my amp did put out rated power.

Its supposed to put out 400 watts at a nominal 2 ohm load and if you look at the numbers I averaged 400 watts.

Do you see the impedence rise at 40 hertz and 50 hertz and look at the wattage.

[ISO]

Everything you need to know and more.

Have fun.

[BigPimpin91]

Hers an example of a kicker ZR360 running to 2 10 inch solo L7 tens with a nominal 2 ohm load.

Volume-----Frequency-----AC voltage----AC amperage-----ohms------watts

31 --------------20--------- ----41.4------------10.7 -----------3.87------- 443

31---------------25--------------44.1-------------9.6------------4.6---------423

31---------------30--------------44.3-------------9.7------------4.56--------430

31---------------33--------------48.3-------------7.4------------6.53--------357

31---------------40--------------48.9-------------3.75---------13.04--------183

31---------------50--------------38.4-------------3.15---------12.19--------121

31---------------60--------------42.9-------------9.22----------4.65---------396

31---------------70--------------33.5-------------9.16----------3.66---------306

Do you get the idea.

Do you see that even though I am running a nominal 2 ohm load I never hit 2 ohms

but my amp did put out rated power.

Its supposed to put out 400 watts at a nominal 2 ohm load and if you look at the numbers I averaged 400 watts.

Do you see the impedence rise at 40 hertz and 50 hertz and look at the wattage.

The impedance rise in the 40 and 50hz range is here this system burps it's loudest at, correct?

This means that even though the amp is only pushing 180w the system as a whole is acting more efficient?

[ISO]

The impedance rise in the 40 and 50hz range is here this system burps it's loudest at, correct?

I can't prove that as I didn't have a Term Lab meter at the time I did this.

This means that even though the amp is only pushing 180w the system as a whole is acting more efficient?

If I was to burp at that there would be far less current draw than there would be at say 20 or 30 hertz.

Part of the answer is in the quote.

[ALPINE408]

You can't just use a calmp meter. You need a clamp meter and a DMM and need to know the formulas to figure this out.

Sorry I'm at work and on a cell phone so I give short awnsers sometimes I just assume if you have a clamp meter your sure as hell gonna have a dmm

But ya the copy and paste ISO just did sums it up