Does this issue also occur with other sources (CDs or the like)?

How about with coax out from the BS Node? Or even optical, to avoid any galvanic connection?

Thanks for your support!

Bad news, I guess. I did the bit test with all files but no window was displayed showing it had been passed, hence I must assume some issues are prevalent. Normally I dont use my PC at all, but I connected my Win PC via the same USB cable and played all files seeing them being fed into the ADI-2. No window showed up.

I want to check the other aspects mentioned (CD as source, Coax) but so far what to do about the negative bit test?

Sorry, if I am misunderstanding you, but how could you assume it was due to the BS Node if i only did the bit test without the BS Node but with a Windows PC?
Is it correct that the bit test with those files can only be done from a Windows PC but not from an iPad? I wouldn't know how to do the bit test via the BS Node either.
Unfortunately I only have 1 compatible USB cable (USB A>B) right now. If the bit test was possible on an iPad, I could use my USB>Lightning cable.

Bit Test can be done from every device that can play audio, including iDevices of course.

But- it‘s not a test to check if ADI-2 is OK, it very likely is anyway.
It‘s for checking the playback device and it‘s configuration.

The test is simple: play the files with your standard soft to ADI-2.

If the test fails, check if all settings in e.g. the Bluesound Node, are set in a way to transfer the audio 1:1 unaltered, e.g. volume set to 100%.

Thanks a lot. Much appreciated. I sat down and did some stepwise testing with these findings:

- Bit Test: Failed every time with all files bot via Win PC and iPad. BS Node not yet tested due to difficulty to access files. I tried different cables and different EQ filters but to no avail. What to do about this?

- Different sources: I could hear the 'white noise', yes, also on CD.
- Different digital connections: Yes, I could hear it again irrespective of connection method: COAX, Opt-out, USB-out from Node.
- Different recordings: It may come and go depending on the file. It is emphasized by EQ, as previously explained.
- Different chain: Yes, i could somewhat spot the sound also on my bigger loudspeaker setup, but to a much much smaller degree.

Summary and open questions:
I think it depends on the record. This must be the flipside of the Stax 'coin'. Stax earspeakers' extremely high resolution emphasizes the slightest glitches which other systems don't even bring up. Quite 'unforgiving'.
--> Yet, the failed Bit Test is puzzling me. What's next?

To avoid chasing ghosts list some tracks where the noise is very prominent.
So I could counter check if it’s audible here too, on my STAX SR-009.

• Check if “Auto Ref Level” is on. You will see the volume figure shown with dBr instead of straight dB sign.

• Set ADI-2’s volume to -10 dBr.
ADI-2’s meter in the main screen (set to post FX or Dual) should now show roughly -10 dB music level.

• Set your normal listening loudness with the High Amp’s volume control.

• Post a photo of your typical EQ curve.
You need an external image hoster to do so.

I replicated your complete setting, incl. Crossfeed and Loudness, like visible in the link provided.
Played on my STAX SR-009 / SRM-1 MK2 directly connected to ADI-2/4 Pro SE.
Streaming from Tidal Master.

• Girl from Ipanema, Stan Getz, Joao Gilberto, Astrud Gilberto:
Over 70 releases of the track, more or less remastered.

The famous edited single version, with only Astrud singing, appearing in mono and stereo versions.

With DA Filter “NOS” the vocal “plate type” reverb sounds artificial, quite like “noise”.
With my preferred “SD LD”-Filter the reverb becomes part of the music.

The original duett version with Getz’ vocal has a faint noise in the intro of most versions.

• I’m coming out, Diana Ross:
I can find ca. 30 releases of the track,
There is a noise along the vocal, obviously origining from the recording process, most prominent in “The Legacy Collection”.
When the drums chime in, I can’t stand playing loud enough to further hear any noise.

With DA Filter “NOS” the noise sounds separated from the music.
With my preferred “SD LD” filter the noise better integrates into what it actually is, a part of the recording.

• Moanin’, Art Blakey, The Jazz Messengers
More or less the same like above.
This is a 1958 recording, which, for it’s age, has quite a good sound.
Obvious recording overloads in the left channel trumpet solo included.

• complete album collection remastered, Buffalo Springfield
Some soft background noise in the stereo versions audible, nothing to ‘phone home about.

CONCLUSION:
These old recordings are made on analog tape and contain some noise due to the recording process.
In the remastered versions the engineers seems to have partly reduced the noise by some amount, but it comes through of course from time to time.
Your EQ is quite drastic (not sounding bad) and boosts the treble, enhancing  the critical frequencies.

To me the NOS Filter’s huge amount of audible artifacts making the situation worse, creating an unnatural disconnection of noise, reverb and music.
Other filters like “SD LD” are better suited.

In this light I’d view the topic as solved, what you hear is simply what is in the recordings.