Power supply regulators for low power audio circuits have always been a source of controversy. Although technically almost flawless, there have been persistent reports about audible differences between designs. John Walton set out to clear that up, both by sophisticated measurements as well as controlled listening tests. He compared no less than 13 different designs. The conclusions he and his listening panel reaches are partly as expected, and partly total surprises.
A comparative overview of power supply regulator designs with listening tests