Linear Power supplies for DACs...?

I don’t know what VPI claims. I always go back to this quote from @dgarretson in another thread:

I read in one of my father's old MSEE textbooks from the golden age of hifi in the 50's, that a block of iron or other magnetic material in proximity to a transformer will improve coupling action between the primary & secondary windings.

SMPS  can be better depends on who makes it and what it's  in.

THIS MYTH GOES SOMETHING LIKE THIS:

"Switching supplies are noisy."

"Linear power supplies are best for audio."

We disagree!

About 5 years ago, Benchmark stopped putting linear power supplies into our new products, and we replaced them with switching power supplies. We did this because linear supplies are too noisy. Yes, you read that correctly, linear supplies are noisy! A well-designed switching power supply can be much quieter than a linear supply.

I read in one of my father's old MSEE textbooks from the golden age of hifi in the 50's, that a block of iron or other magnetic material in proximity to a transformer will improve coupling action between the primary & secondary windings.

Thanks, @mkgus. This info gives me something to research.

I used MCRU LPS with my Chord 2qute.
The result was a very odd, unbalanced, not organic, unmusical sound.
I read a number of other people reported similar bad results with LPS.

Yes, there are more positive reviews about usage LPS with Chord DACs.
But my Chord 2qute sounded so horrible with MCRU LPS, so I don’t believe to these positive reviews at all.
I guess these people just try get positively anything they bought and changed in their systems.