It should belong to this thread as well. I was doing tests with 4.7ohm//33uF load, which at 1kHz represents 3.3ohm impedance magnitude and -45° phase. Please take into account that only at 1kHz. Parallel 4.7ohm//33uF combination equals to serial combination of 2.41ohm + 67.75uF at 1kHz. The amp was doing well with this load, at 1kHz, and the result was posted
here.
It says that the 33uF capacitor did not send the amp to oscillations and the high order feedback loop was working well.
So I have decided to re-measure the amp with the original load of this thread, 4.7ohm//2.2uF, hoping that some miracle might have happened to make it stable. But it did not. The result was same bad as in this thread, and the new measurements are posted
here.
So, it is confirmed, without any doubt, by independent measurements with an audio analyzer, then with a fast digital oscilloscope, and finally by ears and speaker, that the NC252MP is unable to work with the 2.2uF load properly. The high order feedback loop goes to oscillations near 70kHz, there are audible by-products near 6-8kHz, the noise in audio band rises from original tens of microvolts to audible millivolts and the distortion accelerates of 60 dB higher than normally. So there are areas of capacitive load range where the NC252MP is able to work properly and another areas where it is not able to work properly. Neither usual reviews nor datasheets would give you this info.