Personally, before spending on an expensive PSU, I’d rather invest the additional money into an ADI-2/4 Pro SE instead, which can give more return on it if it’s extra features are needed.

Here are some facts and thoughts about PSUs for ADI-2:

You have to keep in mind, ADI-2 produces all it’s multiple internal supply voltages with a combination of a built-in SMPS, followed by a number of Linear Regulators.
The external 12 V supply is just the basic energy source to be further conditioned by the internal supplies’ stages.

ADI-2’s enormous dynamic range beyond 120 dB wouldn’t be possible if there were any “dirt” on these internal DC voltages.

IMO a device that needs an extra, four figure $$$ external PSU to sound best has design flaws.
And then there certainly is some amount of placebo effect too.

Finally it’s your decision and money, and there are companies out there willing to take more of it than ADI-2 Pro costs for an Uber-Ambitious designed PSU .

Some other postings on the issue:

https://forum.rme-audio.de/viewtopic.ph … 75#p198275

https://forum.rme-audio.de/viewtopic.ph … 26#p187926

Legend:
SMPS = Switched Mode Power Supply
LPS = Linear (regulated) Power Supply

Here a view on the differences ADI-2 Pro vs ADI-2/4 Pro SE:
https://forum.rme-audio.de/viewtopic.ph … 47#p198547

If the MC cartridge is “high output” and/or you use a step-up transformer or a Pre-Peamp, you can connect it to ADI-2 Pro SE too.

Currently I have an Ortofon OMP 40 connected (Output 4 mV), and still 12 dB gain reserve left.
So down to 1 mv output MC would work too.

There is no “1:1 feed-through of analog signals, wouldn’t even make sense on such sensitivity signals like from an MC-cartridge.

I did a comprehensive Level Matched Blind A/B comparison, it ended 49:51 better sound one or the other.

There are sound differences if non-standard DA-Filters are used, as AKM and ESS offer different shapes for those.
Nothing night and day and a matter of taste - anyway most don’t even hear the differences between the various DA-Filters in the same unit.

Both ADI-2 have the same XLR/TRS combined socket as anlog input.
A simple TS-RCA adapter is all that’s needed for standard RCA cables:

Aside from ADI-2/4’s phono/RIAA preamp capability and the needed fitting input impedance both ADI-2s offer similar quality.
Most line sources, including home Hifi, don’t care about the different impedance.
ADI-2/4’s level adaptability range extends non significant (3 dB) to the lower.

Personally I can tell:
ADI-2/4’s phono input is more than just a nice add - it sounds and works RME-typical very good, clean and with no added noise, and makes me listen to my vinyl collection more these days.

My choice, if prices aren’t on a premium, ADI-2/4, else I would bit my @#s once I could use the extras.
Of course, if non of these do mean anything, ADI-2 Pro offers the same qualities.

It all boils down to some simple answers:

99% of the info that is present on the net is based on parrot-fashioned spread hearsay, myth-building, expectation bias, comparisons with non-matching levels or parameters, and some intentional misinformation to sell uber-expensive stuff.

There’s a smaller group of very loud opinion leaders and self declared “experts” who often lack even the basic’s of knowledge, defending their self-built myth’s in a religious way.
There’s not much place for simple fact, vs ”religion”.

Did you notice: for those people always the more expensive “sounds better” - how can that be?!

Personally, if I give information it’s always based on my own experience only:

I have, e.g., conducted and participated at a countless number of thoroughly executed Level Matched Blind A/B or A/B/X comparisons of all types of audio equipment and audio codecs:

DAC’s themselves do not tend to sound different with the high development level reached these days - if they are set with the same parameters like same output- (reconstruction-) filters.
But - people don’t know about the filters, so compare apples to oranges and no wonder find they taste different.

Then the laymen tend ro concentrate on the visible or tactile obvious, like “heavier” built, to judge like: “bigger is better”.

But this is not the way audio design works.

It’s all about well-though out circuits, including the component layout and circuit trace routing, that makes the difference.

With a bad design you need a lot of metal screening, even external PSU’s to achieve good results.

Just lately I’ve seen review and measurements of a five figure $$$$$ phono stage with built in PSU, that got 3 to 5 dB better SNR when used with an external five figure $$$$$ PSU - the designer wasn’t able to construct the phone stage properly in the first place, sounds like a bad joke at this price point. (*1)

ADI-2/4 Pro SE’s phono input is a good example of the opposite:
Although built into the same box with no extra screening, it’s free from any stray-noise from the internal digital circuits - that’s good audio design.

(*1)
https://www.stereophile.com/content/ana … eamplifier

”...The current input noise (CH calls it the equivalent input noise, or EIN) is specified as <–135dBu without the X1 power supply, or <–138dBu with the X1, ...”
... “ The EIN specs for the voltage gain input are also impressive: <–130dBu without X1, <–135dBu with X1”...