Distorded sound with Tidal

Sorry for the long post (and for English mistakes, I normally speak French) - If anyone can help me with my technical issue it would be very appreciated! But since this community shows an extraordinary level of knowledge, I am taking my chance!  I tried posting my problem on ROON forum with no success.

ISSUE DESCRIPTION. When streaming Tidal on my system, on some tracks I hear some disturbed trebel (let say in the area of 4KHz +/- 1KHz). It is difficult to describe - it reminds me the sound of dirty (dust) needdle playing a record. For example, I hear that crysp on Ella high notes. I also hear it on some cymbals (rides, for example). Sometimes it is more obvious; sometimes it is subtle.

PATTERN. I have not been able to identify a pattern on when it happens. It could be on 16/44, on 24/192, and everything in between. It seems more frequent on MQA (what ever the resolution). Week ends, week days, day time, night time, none seem to have influence (I was thinking power grid pollution)

EQUIPMENT

Tidal HIFI + FLACs on hard drive
NUC I7 (7th) with ROCK/ROON, USB connected to:
IFI micro I-Link USB to S/PDIF converter (24bits/192KHz capable), connected to S/PDIF of:
Audio Alchemy DDP-1 (Preamp and DAC + external power supply), driving A and B:
A: Audio Space AS-3I (tube amp EL-34) integrated amp that drives Reference 3A MM speakers
B: MiniDSP (low pass @ 80Hz) that drives Simaudio W4150 solid state amp that drives DIY subs

POSSIBLE CAUSES
-ROON Issue: Tested Tidal outside ROON (on a laptop) - no improvement
-Faulty Speakers (tweeters). Tested two other sets - no improvement
-Faulty DAC/Preamp - tested with a different DAC (Moon 100D that can only accept 24bits/96Khz) - no improvement
-Faulty amp - tested with a solid state amp - no improvement
-Faulty USB converter - not really tested but streaming directly from a Lumin M1 shown the same problem - no improvement
-Faulty NUC - tested streaming from a laptop - no improvement
-Noisy outlet (AC supply) - tested a few power cords ($100 to $200 each) + connected to different outlets + added power conditioner ($400ish) - SURPRISE! 50% improvement mainly due to using a different outlet in the same room ($2 type of outlet).

• I also tested streaming directly and from my NUC to a Lumin M1 at my cottage (different power grid, different network, different speakers) - no improvement perceived
• I tested streaming from my hard drive (tested different quality) connected to the NUC - the result is no issue, no distortion - only distortion in Tidal.
• I tested streaming from Spotify (highest quality but still a low streaming rate compared to Tidal) - the result is no issue, no distortion
• LAST TEST: in ROON I decreased Tidal quality from HIFI to the next lower level (forgot the name) - distortion seems to be gone completely or almost (but I am loosing overall sound quality).

HELP
I suspect a mismatch between equipment but I am surprise to hear the same issue with different equipment (Lumin M1) in a different location (my cottage). I also suspect that the internet quality and supporting hardware may be the cause (low speed at the cottage and poor CAT5 in-wall cables and poor switch at home).

Do you have any suggestion for the cause or a test to propose?