This is my amplifier load. Since I don't need uber accurate test data, this load
works pretty good.
http://home.pacbell.net/lordpk/load/
You get electric water heater elements from the home center and measure their
resistance and proceed to series/parallel them as desired. In my case, not
shown in the pics, is switches to configure different loads.
I have seven 5kw elements, power handling is 35kw which is overkill.
To make the load more stable, you want overkill as when elements change
in temperature their resistance changes a bit. It's ideal to keep the temp
low on each one by using many elements and filling the bucket with water.
Actually, for 2kw or less, I don't need water unless the test is running for
a long time.
Test the resistance of the load before the test to ensure it meets your
target resistance goal. Then run the test for a while at low power to warm up the elements,
then run the test at full power to get the final measurements, then immediately disconnect
the load and measure it's new resistance value as it may swing a few 1/10 of
an ohm as it changed temperature. Use that resistance value.
Play a low frequency sine wave {60hz works} --just in case- there is high inductance, scope the signal and ensure it's not clipped, then use the DMM to measure AC rms voltage. Do the math and you have a good idea on what
the amp does but you don't know the distortion level.
