Amp Benching?

[Buck 5,000+ posts]

Where do you buy a clamp at? (to measure amps)

 

[n2audio 5,000+ posts]

most hardware stores will sell a decent clamp meter. Sears has one.

 

[Buck 5,000+ posts]

most hardware stores will sell a decent clamp meter. Sears has one.

You know how much it costs?

 

[n2audio 5,000+ posts]

http://www.sears.com/shc/s/search_10153_12605?vName=Tools&cName=Electrical+Shop&keyword=clamp+meter&sLevel=1&sLevel=0

harbor freight has some cheap options. No promises on quality or accuracy though.

 

[Buck 5,000+ posts]

http://www.sears.com/shc/s/search_10153_12605?vName=Tools&cName=Electrical+Shop&keyword=clamp+meter&sLevel=1&sLevel=0
harbor freight has some cheap options. No promises on quality or accuracy though.

I appreciate it man.

 

[bikinpunk 10+ year member]

MOST IMPORTANT THING IN THE BCAE LINK:

Test Data:

The following data was taken in a test to show how calculating power when using the voltage across a speaker's terminals instead of the voltage across a non-reactive dummy load will result in false output data. The frequency is the test frequency. The voltage is the voltage that was measured across the terminals of the load (either speaker or dummy load). The power is the calculated power using the speaker's nominal impedance (4 ohms) and the voltage across the speaker's terminals at the various frequencies. The voltage across the dummy load will be virtually the same across the range of frequencies so only one voltage reading was necessary. The amplifier is capable of producing only 205 true watts (RMS power). When using a speaker, it appears to be able to produce as much as 376 watts (which it clearly is not capable of doing).

Check the table:

 

[CrazyKenKid 10+ year member]

MOST IMPORTANT THING IN THE BCAE LINK:

Check the table:

sorry so what are you getting at? using a speaker will screw up your readings? so you wnat to use a dummy load or resistors?

also what frequency should i be using with the dummy load/ resistor bank? 50 or 60 hz? (ps i will be using a frequency generator to give me the wave)

 

[n2audio 5,000+ posts]

freq doesn't matter when using a resistor.

it is generally done at 1khz - not sure why - my guess would be it's in the middle of the easiest range to reproduce.

 

[Buck 5,000+ posts]

freq doesn't matter when using a resistor.it is generally done at 1khz - not sure why - my guess would be it's in the middle of the easiest range to reproduce.

Wouldn't it be different depending on what frequencies that specific channel or amp is playing.

 

[gunz4me 10+ year member]

BCAE is opposite of what I have shown.... I have managed to show more power off of dummy loads than the actual subwoofers.... go figure....

 

[n2audio 5,000+ posts]

Wouldn't it be different depending on what frequencies that specific channel or amp is playing.

no, "dummy loads" are resistors. The resist at X ohms regardless of frequency.

an amp may produce slightly different power at different freq's, but it shouldn't vary much. That's why power ratings SHOULD (and used to) be specified as X watts into Y load +/- NdB from 20-20khz.

 

[CrazyKenKid 10+ year member]

so since dummy loads cost to much looks like i am going to buy a bunch of 2ohm, 20watt resistors! i got a price of like 100$ shipped to my house! lol!!

fun times hooking them up in a 10x10 setup lol!!

 

[gunz4me 10+ year member]

Take your multi-meter to some home improvement stores and test hot water heater elements for DC resistance. I had 3 12 ohm elements that could be used as a dummy load, and I submerged them in automatic transmission fluid to keep them cool. Unfortunately, I can only find 2 of the three //content.invisioncic.com/y282845/emoticons/frown.gif.a3531fa0534503350665a1e957861287.gif