known problem. discussed in this forum before. no way to fix it.

My experience:

I'm cannot hear very high frequency noise well due to, well, tinnitus. probably the top I can hear is 15khz.

The old ADI-2 Pro FS model's display was worse and I could hear a constant ~10khz tone when I close my ear to the screen.
And with the adjustment of display brightness from low to high, I can hear another but higher 10khz tone from high to low.
For the upgraded Pro FS R I now possess, the display is a lot better, as the 10khz tone is now gone. Only the variable frequency depending on the brightness setting.

But in any case, I can't notice the noise when I sit 2 feet away at all.
Also, because I'm using the lowest brightness, the tone moves to a higher frequency so I can no longer hear it, even if I put the screen right on my ear.

I think those
1) who can hear high frequencies really well 
2) whose ADI-2 screen has a higher noise than normal due to variations
3) who happens to sit very close to the device
are really rare. So very few people think this is an issue and report it here.

Maybe you can chat with your dealer and see if they can show you a demo unit to check if the screen is quieter, or just set the brightness to some frequencies you cannot hear.

>  in my case USB connection is mandatory for noise to occur.

With a microphone I can confirm it's louder when USB is connected.

> You said here that there is no way to fix it. Does this issue exist in all units? Or it varies from one to one?

My reply above is updated to give you more info.

There's some unit to unit variations.

As I said, The new screen is already better than the old one (which gives fixed 10khz tone).

The best way is to talk to your dealer and check if you can get a demo unit for check.

Again this is a very rare issue (the above 3 have to be met at the same time),

I would suggest avoid sitting too close, and tune your brightness so you can't hear it.

Thanks for all of you for such comprehensive answers.

Notice, that in my case if display is off, squeak becomes completely inaudible. Do you think that voltage regulator ‘fix’ should help?

Yes I probably would Johannes.

Then too:

If a Tree falls in the Forest, and no one is there to hear it, did it make a sound?

Curt

Unluckily I have the same issue on my unit. I have returned it and got a new one, but the problem is still there. That noise coming from the front of the unit is variable when you change the brightness (the peak is at 80 % of intensity in my case) and is more intense when you regulate the volume. Both of the units I had were identical regarding the circumstances in which the problem is showing up, so I think most of the new ESS units are plagued by this. In auto dark mode the problem is not there, but for 1.000 € I expect to keep the display on without sacrificing anything.

Neither RME nor Thomann were aware of this problem and I am still waiting for news. Both of the customer services were however very kind and willing to solve, so I expect that I am gonna solve it in a way or another (even if the end is gonna be shipping back the product).

I also recorded a small video, where the noise is clearly audible starting from second 0:08. https://we.tl/t-Vrn0lS6m8D

No, I read it. But the RME support forwarded me to Midiware, that forwarded me back to Thomann. I would gladly send my unit to RME to fix the problem, but I don't know who I should contact now, since the official support said I should rely on my local reseller (Midiware), which said I purchased it out of their distribution network so I can't have their support. Thomann (the reseller from whom I purchased the unit) told me I should contact RME. In the meanwhile, Midiware answered a second time, telling me that they have contacted RME, which told that the only thing I can do is to return the unit to Thomann and have back a new one (like I already did the last month), so I am in this endless circle. Can you please address me to the correct channel to have my unit shipped to RME and fixed? It's not a problem at all to ship it in Germany.

I apologize if I seemed rude. That wasn't my intention. I also quoted the post number 6 in my communications with Thomann and Midiware, but I wasn't proposed to fix the issue in the way you mentioned. Thanks in advance, Matthias.

The part producing the tone is sometimes silent, sometimes not, so there is no way to match this with serial numbers, it is random. And there is currently no change in sold units. Getting different parts takes a long time these days.

Thank you. In the meanwhile I got in touch another time with the RME support and they told me that I should go through Thomann which should fix the unit with Audio AG. I am gonna try to coordinate them and see if I can send back the unit.

A month after the noise has been fixed, I have to say that the ADI-2 DAC FS is probably the best audio equipment I've ever bought in a long time. After it's been repaired, I enjoyed listening to my favourite music without hearing the electrical noise. I use only open headphones and I can't hear the noise unless I put my ear (without wearing headphones) really close to the DAC, which is not a listening scenario. I also had the opportunity to compare my ESS version to the AKM version of a friend and it's impossible to hear a difference. So, now that the problem is known, I highly recommend this device. You buy it and you can forget about upgrading headphone DAC and amp. I also subscribed to the YouTube channel where I appreciate the transparency of the company in giving updates.

Don‘t be worried. Sooner or later age will cure your problem anyway.

Contact our support or Audio AG, the info that you got from Thomann is not correct.

Third new unit arrived here, same problem.

Tried involving Audio AG. Audio AG wrote they were sure it is a problem with the power supply, they would have tested power supplies. So I sent the (new) power supply back to Haimshausen at my cost and got a "tested" replacement back. Except the noise from the device did not go away. The noise also does not change when compared to a non RME 12V power supply.

Now Audio AG got back and said there were a misunderstanding and they will also repair/swap the device… next try I guess.

Just to add my recent observations with this matter:
I just received a new ADI-2 DAC FS which exactly had the described problem.
Another brand new replacement unit I got from the store had the same issue.

The image shows the spectogram (10kHz to 20kHz) of an audio recording next to the device while turning down the screen brightness from 100% down to 20%.

In the current state I cannot use the device and hope that this will be resolved in the future.

I received a unit (ADI-2 DAC FS) from Sweetwater on 7/15 with this issue. High pitch noise that I can hear from half a meter away, with a tone that changes when I adjust the display brightness. Also observed that the sample rate has an impact on the tone. A replacement arrived from Sweetwater today (7/19), but it has the same issue.

I love the functionality of this device, but it's not usable like this. Kinda defeats the point of -110 dB SINAD if the device produces audible high frequency noise that I can hear sitting normally at my workspace.

Thanks Jeff, that's great news! Would love to have a working unit.

I gave Sweetwater both options (send to you, vs. try for a third pre-tested unit at Sweetwater).
Will definitely reach out if they choose the first option.

Has this been fixed for all the new units yet? Or should I still wait a year or two before buying a unit? I am not in a hurry and I want to avoid getting myself stuck in any sort of warranty limbo.

For what it's worth, my experience with Sweetwater was great. After I sent the second unit back, they sent it to RME (probably Synthax?) for repair. The repair took less than 2 weeks, and I had the unit back in less than 3 weeks.

The unit I received back has zero audible or measurable noise (above room noise floor) at 352.8 kHz sample rate or above. Below that, I can hear a ~15 kHz noise at <10cm and (barely) measure the noise at <50cm with a mic. This is with the display at 80%.

Can you disclose what is being modified during this fix?

My device is a squeaking one, but now I don't care. After the honeymoon period, I still admire its features and craftsmanship. I'm sure that I'd buy it again. Sure, squeak is a scar on the picture, but small one.

The solution is to find a unit with the good old AK4493 chip. This noise issue is only affecting the new ones with the ESS chip.

Anyone has any idea?