why the classic THD is a worthless specificationWhy pick on THD?
This thread https://www.diyaudio.com/forums/power-supplies/143539-look-lm317-lm337-regulators.html on regulator impedance is very interesting before it devolves.
Mr. Bau graciously modified the P.S. in my Rotel RCD-02 for Linear Z. The improvement is nothing less than astounding. As close to studio playback as I've ever heard.
There’s a lot hi-falutin’ gear out there with 10¢ power supplies...