General questions: Amplifier PSSR, caps and noise floor

I've been led to believe that unregulated sounds better...
Questions of PS influence on amplifier sound are here discussed mostly anecdotally. Another issue, as I see it, is that almost all regulated power supplies at diyAudio are presented without any measurement or simple ripple and noise value at best, thus making facts based comparison impossible. There are rare exceptions, most notable being legendary Linear Audio PS testing session, with detailed measurements and listening session. From that session, Jack Walton shared here some very interesting tidbits about transient response and PS rail harmonics. Most interesting is, that he was able to confirm listening test rank of power supplies by measuring their rail harmonics under load. So, one theory why different PS may change sound of an amplifier, is that different PS produce different rail harmonics under load and that is the cause of subtle sound signature change. The same may be true for using various boutique PS capacitors.

I have no conclusion on this, only questions. Here are comparative measurements on regulated PS and simple CRC.

1W.png


CRC 1W.png


CRC PS produces rail harmonics at several mV range while regulated remains at uV range. At 10 W, CRC produces 10 mV H2 harmonics and that is 59 dB below output signal. As there is some PSRR, I’m not sure this can affect amplifier sound. I believe that transient response is more important.
 
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