Has anyone who has gone to a linear PSU done any measurements that demonstrate improvements to stability, distortion, jitter, amplitude vs frequency or any other characteristics? I am mulling the possibility but haven't seen enough justification yet. My limit has been grounding the SMPS common to stop it biting.
Well, aside the mains leakage protection a linear and good stabilized power supply will do jack against jitter (digital issue), frequency stability (oscillator) and amplitude vs frequency.
It will do a lot of good on: distortion factor of high signal levels under load, noise factor and make the amplitude more predictable. I mean if you connect a 1Mohm scope probe, you won't see too much of a difference, if you connect a 50ohm spectrum analyzer input and play a bit with the levels you'll see the difference immediately, also one can connect a scope with a 50 input and put the triangular waveform.
Someone here did the measurement and the output voltage of the power supply swings in between 12 to 17V !! volts, in different load and frequency conditions, this can't be healthy for the analogue block.
Cheers,
DC1MC