It looks like he may be  using an active  power conditioner, not a passive power distributor strip,  for all his equipment.

I've tracked down the hum issue. I have dual subs and was using XLR into them (didn't have long enough RCAs), with RCAs into the amp. It sounded soft to me, so I unplugged the RCAs from the amp, and ran short XLR from RME to amp... not using the subs; however... the RCAs were still plugged into the RME. When I touched the pin for the RCAs, the hum got worse. When I unplugged the "unused" RCAs from the RME, the hum went away... almost entirely. There is still a very little amount of hum, but nothing like before. Also, with just the XLR plugged into the Ayre VX-5 Twenty, and touching the shell of the XLR, I could induce a bit of hum. By design, the XLR inputs for the Ayre VX-5 Twenty do not have the metal locking clip on the female connector on the amp... because it's steel and can become magnetic. They thought that was an important detail. Making sure the XLRs were well seated into the connectors on the Ayre amp, and touching them a bit more seemed to resolve the issue more such that I am now satisfied.

So, it's possible for the 2 different output connections to induce noise into one another.  I wonder if caps of some sort for the RCA outputs, if they are unused, would be a good idea.

The XLRs I'm using are Mogami 2549 wire with Neutrix connectors. The 2549 wire is 2 conductor wire, with a shield. Mogami makes a 2534 wire that is a quad conductor wire that is supposed to be even more resistant to noise. I am going to try to get my Mogami 2549 wire as "happy" as possible and check anything it is running close to. I think I've already gotten it to that point, but will continue to fiddle with it.

For those interested, below is the description for the Mogami 2534 wire, said to be more noise resistant. Supposedly the advantage of the 2549 wire over the 2534 is lower capacitance and more extended highs with the 2549.

Bottom Line: It appears the RME ADI 2 DAC FS is just very sensitive to sources of noise, but it can be dealt with. Be very particular about how wiring is routed, etc.  I may even try some longer XLR cables to get the ADI-2 further away from the amp / other equipment... anything with a transformer... isolate the ADI-2 away from other equipment.  It's sitting right next to my Ayre VX-5 Twenty now.  I may also try laying a sheet of carbon fiber fabric on top of the unit.  I also have a few small pieces of "ERS Paper"... I'll throw everything at it.

Mogami 2534
Mogami Neglex quad cable is perfect cable for home studios suffering from wiring and grounding problems. Mogami 2534 should also be used where intense RFI interference is a problem. Mogami 2534 provides an improvement in signal to noise of 10-20db over equivalent twisted pair cables. Double conductors quad cables are more effective in canceling noise that can get past even the best of shields and is critical in an environment of high RF and EM interference. Conductor insulation is XLPE ( Cross-Linked Polyethylene) which has excellent electrical characteristics and prevents shrink-back during soldering. Served (spiral) Bare Copper Shield is superior to foil or braided shields for sound quality and simplifies termination.

@jmimac351

Are you referring to ADI-2 switched off?

With ADI-2 “on”, and all audio cabled fully balanced, hum should be a complete non-issue.

So it’s clear we’re analyzing a useless configuration:
Power amp switched on, but no active source connected, no music playing.

I point this out for a others reading along, to not get a wrong view on the topic.

The explanation for what happens is already there:

• ADI-2 DAC’s XLR output in state “off” is no longer balanced (*1), instead can be regarded as single ended, as one leg is connected to ground but not the other.

• As a result, induced stray electric fields are no longer compensated by the balanced interconnection to the power amp, as it would be when ADI-2 DAC is switched on.

• In this state, every change of interconnects, e.g. plugging an additional RCA cable, changes the amount of stray currents picked up from the surrounding.
To further analyze this is pointless.

• The described symptoms point to, your system not having a connection to safety ground anywhere.
Culprit might be an ungrounded power conditioner, or no device having a 3-prong mains plug.
Here lies the solution:
connect the power amp (preferably), or ADI-2 DAC to safety ground.

Obtaining the ADI-2/4 Pro SE’s 3-prong PSU with soft ground could be a remedy.

Or, an adapter like this one can be used for a safety ground connection:

(*1) Remark:
Standby or powered down - the XLR out’s hot (2) and cold (3) pins - on ADI-2 Pro are both quasi open loop, on ADI-2/4 pro SE both show identical 106 Ohms impedance.
So with the Pro’s the mentioned phenomenon shouldn’t appear, as both stay balanced, even when powered down.

Maybe I need to make that clear, I am a private person, in no way linked to RME.
So what I write is my private opinion, nothing more, and I do this in my private time.

I’ve tried to show up valid and inexpensive solutions in my former posting, maybe you’ll try them out before going further.

I even had a look in the Ayre VX-5 documentation, but couldn’t find any hint why it’s safety grounding doesn’t solve the issue as it should.

Maybe you let a professional electrician have a look into this, I suspect there might be something broken or miss-configured regarding the, for security reasons, very important safety ground.
Or did you do anything to bypass or isolate the Ayre VX-5’s safety ground?
Or maybe you do use non-standard XLR cables, with the screens disconnected at one side?

Regarding ADI-2 DAC:

What happens partly results from ADI-2 DAC’s internal hardware and cannot be changed at this point afterwards, e.g. by firmware updates.
A different power supply (as mentioned) CAN make a difference.

@jmimac
There is good practice that audio devices are switched on in sequence from the source to the amplifier and switched off in reverse order...
So, configuration D/A off and amplifier on goes against this "golden rule"...

Doing other way is possible, but if things go wrong way one risks damage of gear and in the worst case damage of hearing....

So in your use case the best practice is to keep RME always on if you have amplifier always on....

Thanks for your feedback... again... other gear does not have this issue... but I have resolved it.  Yes, normally I would leave all gear ON.  As for damaging hearing?... I don't listen via headphones...

I just sold my Michell Gyro SE table, but will keep that in mind.  If there is some benefit the ADI-2/4 would have for 2 channel audio with dual subwoofers, then I guess I should be looking at that.  I guess the difference (if any) of what is being output from Lines 1/2 vs Lines 3/4 would be of interest.  I'll check it out and try to figure out what the functional differentiators are for my setup. If "Lines 1/2 vs Lines 3/4" means I can apply PEQ to the subs separately from the PEQ applied to the main speakers... then I definitely need to check that out.  However... I have PEQ already directly via the subs... I really just need them linked up for volume... don't necessarily need more complexity.

Thank you.

Well, I took your advice and bought an ADI-2/4 yesterday.  Thank You for your patience and thoughtful advice.

Finally, after several pre-announcements of the DPS-2 RME released their first linear power supply with some cool features.
Please find below the link to the specs, manual and some pictures:
https://www.instagram.com/p/C5MLHB8Mt8j … s4YWd2cDN5

So that was spam by Pervasice?

Cannot fint any info.

Im very very curious about why one would need a manual for a psu?

Products online, they look great!

What are the recommended retail prices?

And when do you expect retailers to be able to deliver?

Not cheap....

https://www.rockshop.de/rme-dps-2
https://www.rockshop.de/rme-lni-2-dc

I am getting one. haha.

I will report if I can hear any differences.

Exciting stuff.

That's right, for the “audiofool” crowd. Not only will you not hear the difference, but you will not be able to measure it.
But I guess if someone has the room in a stereo setup and money burning a hole in their pocket, then why not?!

DISAPPOINTED

I’m 63 years old and have been running a hi-fi system for 50 of those years. I’ve always saw through the sometimes blatantly obvious snake-oil merchants (looking at you Audioquest), and grew to look out for, and appreciate good quality, no-nonsense engineering.

I was therefore drawn to the ADI-2 DAC FS as an exemplar of this. After joining the forum about a year ago and being delighted by the time and trouble taken to answer a noob’s question, I have been extolling the virtues of R.M.E. to friends, family and office colleagues.

So I have to say that, unfortunately, I am more than a little disappointed by the release of a new PSU and an active filter. The RME LNI-2 DC costs £499 on the Synthax Uk website and the RME DPS-2, costs over 1000 euros on the Rock Shop website. I’m reminded of Kais in answer to Mitchlees66 concerning buying an ‘expensive’ PSU saying that “IMO a device that needs an extra, four figure $$$ external PSU to sound best has design flaws.” Now I’ve noticed that RME are quite careful that nowhere in any of the descriptions I’ve so far come across is the claim made that the PSU will make the unit sound ‘better’. 
With that in mind, my question is - So what’s the point?

The manual states that “the ADI-2 DAC achieves its technical specs even with less optimal power supplies. Or in other words: the choice of power supply is not critical.” I would assume therefore that the supplied PSU is absolutely optimal.
Again, with that in mind, my question is - So what’s the point?

Please don’t think any implied criticism of these new units is in relation to their price. Top quality engineering costs top money and I believe RME engineering is top quality. If the RME LNI-2 DC cost just £49 instead of £499 I would feel the same. Because time after time respected members on the forum have rubbished the idea of a ‘better’ PSU, stating quite rightly that according to the manual the supplied PSU is all that is required for the unit to achieve it’s technical specs. This looks to me like a solution to a problem that RME have already solved.

Good luck to RME in selling these PSU’s, but until I see published results which prove an audible, or even measurable, upgrade to sound quality then I will stick with what the manual tells me, which is that the supplied PSU lets the unit achieve it’s technical specs.

By the way, I fully expect to be rubbished, told I don't know what I'm talking about and given some 23 paragraph technical explanation of why the new PSU's are definitely better than the supplied one.

That PSU does not have to be for RME devices... Or may serve for achieving better measuring parameters of some RME devices. Or may be developed for future RME devices.... And so on....

I have, you have, everybody has, one would only need to dig deep enough.
Recordings, BTW, contain it.

But - as I always say:
If you don”t hear noise (or hum) you don’t have a noise problem.

Not

Or "peace of mind" like the other guy said. I bet some people struggle with having a PSU akin to a laptop adapter in their precious systems, regardless of measurements and end results.

I dont have the grounding and hum problems these devices are meant to solve, but my main objection is really norwegian currency plummeting against euro on top of inflation. That goes for alot of buying these days. TBH I suspected DPS-2 to retail at half the listed price. Its very expensive taking the better half of an ADI-2 pro

Sad, because these seem like really solid products.

Is it designed so you connect the ground of your turntable to the ground connector on the PSU rather than to the back of the ADI 2/4 Pro?