@amir_asr "They make very rudimentary measurements often using obsolete audio analyzers”
Dear, your APx555 with -117dB NF is outdated to measure my -124dB NF DAC :-), not talking here about RFI/EMI noise polluted environment.
nice try though!
I already corrected you on this in the last thread. Here is the results of a recent review again:
As you see the analyzer has no problem measuring dynamic range of 130 dB for this DAC. Your 124 dB DAC is good but is 6 dB or one whole bit worse than this unit. If you are charging more than a few hundred dollars for it, I suggest going back and redesigning it to lower its noise unless you are having noise pollution as you mention.
You also looked up the wrong spec for APx555 analyzer. The -117 dB is THD+N. This is a worst case spec (company is very conservative in this manner). I am able to measure THD+N to -124 dB:
With FFT analysis like above, we can dig as low as we want as far as distortion spikes anyway.