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I hate to say it as I've been one of those asking for reactive testing. Looking more closely now, I think it is of very little utility. I think testing into 1, 2, 4, and 8 ohms is really all you need (though I'd like the addition of 16 ohms). It appears using tone burst testing will do it so very little danger to the DUT.
Basically you need to know the amps current, and voltage operating envelopes. And you don't need reactive testing to do that.
If for completeness sake one still wishes to actually test into a reactive load I think the following Power Cube results indicate it is a waste of time to test at 30 and 60 degrees. Things could be simplified by testing only at 0 and 60 degrees. Those inductive tests mainly point to amplifier instability. So you really only need the more extreme test to indicate it is happening in a given amp. So that alone would simplify what is needed for a reactive load.
Here are some results from the Power Cube test. I think you'll see even when the result wasn't close to great you didn't learn anything you couldn't learn from a straight resistive test. A simple graph of volts over impedance will show plenty about the amps capabilities.
KRELL KSA 80B
8Ohm
158W 60deg Cap
157W 30deg Cap
156W 0 deg
157W 30deg Ind
159W 60deg Ind
4Ohm
303W 60deg Cap
294W 30deg Cap
292W 0 deg
296W 30deg Ind
302W 60deg Ind
2Ohm
557W 60deg Cap
518W 30deg Cap
506W 0 deg
518W 30deg Ind
545W 60deg Ind
1Ohm
403W 60deg Cap
407W 30deg Cap
421W 0 deg
417W 30deg Ind
332W 60deg Ind
MCC POS: 70A
MCC NEG: 0A*
*could not measure ?
from:
KRELL KSA 80B
from: https://www.diyaudio.com/forums/solid-state/78129-krell-ksa-100mkii-clone-post1974700.html
from: https://www.biline.ca/audio_critic/audio_critic_web3.htm
from: http://erha.se/~ronny/hifi/xtz/a100.htm
from: https://www.biline.ca/audio_critic/audio_critic_web1.htm
Basically you need to know the amps current, and voltage operating envelopes. And you don't need reactive testing to do that.
If for completeness sake one still wishes to actually test into a reactive load I think the following Power Cube results indicate it is a waste of time to test at 30 and 60 degrees. Things could be simplified by testing only at 0 and 60 degrees. Those inductive tests mainly point to amplifier instability. So you really only need the more extreme test to indicate it is happening in a given amp. So that alone would simplify what is needed for a reactive load.
Here are some results from the Power Cube test. I think you'll see even when the result wasn't close to great you didn't learn anything you couldn't learn from a straight resistive test. A simple graph of volts over impedance will show plenty about the amps capabilities.
KRELL KSA 80B
8Ohm
158W 60deg Cap
157W 30deg Cap
156W 0 deg
157W 30deg Ind
159W 60deg Ind
4Ohm
303W 60deg Cap
294W 30deg Cap
292W 0 deg
296W 30deg Ind
302W 60deg Ind
2Ohm
557W 60deg Cap
518W 30deg Cap
506W 0 deg
518W 30deg Ind
545W 60deg Ind
1Ohm
403W 60deg Cap
407W 30deg Cap
421W 0 deg
417W 30deg Ind
332W 60deg Ind
MCC POS: 70A
MCC NEG: 0A*
*could not measure ?
from:
KRELL KSA 80B
from: https://www.diyaudio.com/forums/solid-state/78129-krell-ksa-100mkii-clone-post1974700.html
from: https://www.biline.ca/audio_critic/audio_critic_web3.htm
from: http://erha.se/~ronny/hifi/xtz/a100.htm
from: https://www.biline.ca/audio_critic/audio_critic_web1.htm
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