i was just wondering, if i'm going to check amp draw (12v) to the battery, what's the best tool to use? i was looking for an amp clamp, but they seem to be ac volts only, also, when checking ac output, should the woofers be hooked to the amp? this may be a stupid question but i know different impedence changes the output of an amplifier. can anyone help?

 

A clap should also measure AC current...

Basically you need 2 meters... 1 AC clamp for current and another DMM for AC volts.. (both should be a True RMS meter)

Measure the 2 at the same time (you can't do 1 and then the other)... then multiply ac current x ac volts.. and you've got your output.

Yes, you want the subs to be hooked up.. because you're measuring the power to the subs from the amp.

Also... measuring will give you the resistance that the amp sees at the time of measurement.

 

your amplifier's power output depends on your box.

 

i see, excursion +/- would change the impedence and the box limits excursion, and/ or cycles per second. kinda?

 

Many clamp-on meters read DC as well. I have a Fluke 336 that reads up to 600 amps AC/DC.

A compilation of what's mentioned above, use 1 meter to measure output voltage, one to measure current, and use a constant tone (like 50 Hz for example), as the box/speaker combo will change impedance as frequency changes, making your output numbers vary.

 

i see, the amp clamp i have is ac amps only and not true rms, i may have to wait to do this.