True RMS question

[bjfish11 5,000+ posts]

Ok, i used my multimeter and go a readout of 14.68 volts at the terminal. Then, i used my craftsman true rms clamp meter and hooked it around the positive wire coming into the amp and got around 44 amps. Multiply that and i get 652.92 amps. This is on an orion 1200, what am i doing wrong?

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[squeak9798 5,000+ posts]

Sounds like you are doing something wrong....

Accord to ohm's law, that should have been a ~.33ohm load that you were powering. Is this correct ?

More details. What do you have the Orion connected to? At what nominal impedance? What is the voltage output with a sinewave and no subwoofers connected?

That voltage output just seems way too low.

 

[bjfish11 5,000+ posts]

oooo....im an idiot. **** its been a long week. I was doing voltage input instead of output, guess its back out to the garage to do some more figureing.

 

[squeak9798 5,000+ posts]

oooo....im an idiot. **** its been a long week. I was doing voltage input instead of output, guess its back out to the garage to do some more figureing.

LOL.....yeah, you just pwnd yourself //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

 

[bjfish11 5,000+ posts]

well from one end of the spectrum to the other. Here is more info.

2- dual 4 type r's wired to a 1 ohm load. NOW, i have 43.7 amps and 49.3 volts. Set gains with a o scope and a 50 hz test tone. Same tone and settings i used to get these numbers. Now i get 2154.41 watts. What am i doing wrong?

 

[squeak9798 5,000+ posts]

Clipping your amp possibly. Or atleast driving it past it's "clean" output limitations.

Again, according to ohms law, that would net an ~1.12ohm load. Which may be accurate depending on the frequency and impedance rise of your enclosure.

 

[bjfish11 5,000+ posts]

i set the gain with an oscope, so i would have to rule out clipping, wouldnt i? I used the same volume and settings and same test tone when setting the gains as i did to get the numbers i got.

 

[bjfish11 5,000+ posts]

anyone?

 

[bjfish11 5,000+ posts]

squeak, come back. i need help

 

[thch 10+ year member]

well from one end of the spectrum to the other. Here is more info.2- dual 4 type r's wired to a 1 ohm load. NOW, i have 43.7 amps and 49.3 volts. Set gains with a o scope and a 50 hz test tone. Same tone and settings i used to get these numbers. Now i get 2154.41 watts. What am i doing wrong?

hmm. odd. i would think you would be getting 34V, 34A.

just for fun -- this is the output current and output voltage right? make sure you aren't measuring output voltage and input current.

 

[squeak9798 5,000+ posts]

squeak, come back. i need help

Oh yeah...sorry..LOL

One of your pieces of equipment might be reading incorrectly or you have one of the settings set incorrectly. Or you are still taking measurement incorrect measurements like thch pointed out.

Your voltage is still really high for that amplifier. Even assuming the amplifier is underrated and can cleanly produce 1500w @ 1ohm, that'd still only be ~38V. Because, yeah, the Orion is underrated, but not as heavily as you are measuring.

Maybe the o-scope you used to set the gains with is inaccurate?

I'd try finding a different DMM and/or clamp meter and measuring again.

 

[bjfish11 5,000+ posts]

i guess im doing this wrong.

Ok, i did take the output voltage. But for the current, how do i take the output current? I was putting my clamp meter around the input power, i tried on the output current but it didnt have a reading. This would be dc right? Maybe my dmm is off, ill try it later using the clamp meter to read the voltage. This is a brand new clamp meter, first time i used it, and ive only had the oscope since christmas.

 

[squeak9798 5,000+ posts]

i guess im doing this wrong.Ok, i did take the output voltage. But for the current, how do i take the output current? I was putting my clamp meter around the input power,

//content.invisioncic.com/y282845/emoticons/crazy.gif.c13912c32de98515d3142759a824dae7.gif

There is your problem //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

This would be dc right?

No, sinewaves/music are AC. The clamp meter should be set to AC and test the amplifiers output.

Though I find it a little odd that at full power output with a sine wave you were only pulling 43A from the electrical system. You would need to draw atleast double that to even have 1200w of output on a 14.4V electrical system...and that's not even taking efficiency into account.

 

[bjfish11 5,000+ posts]

soooo....i need to meause the outcoming volts and amps in ac? And where do i need to put my clamp meter to read the current? Around the positve speaker wire? Sorry for all the stupid questions.

 

[bjfish11 5,000+ posts]

ok, here is what i got now:

13.8 amps with clamp meter around positive speaker wire running to subs

43.7 volts with dmm connected to speaker wires with subs unhooked.

What am i doing wrong?

Could someone please walk me through the process?