The noise from a TL431, for what that's worth, varies with the closed loop gain (i.e. the voltage it's set to), if used as per the data sheet.

The LM3x7 / 1086 types can make noise independant of output voltage without sonic penalty.

You can mod the 431 circuit to reduce noise gain, but this affects the loop characteristics and may have sonic ill-effects.

Personally I think TL431's suck, sonically

 

This is true, simply because of the different open-loop characteristic. Not sure it tells you anything about sound though.

Andy.