How to proceed?

@stuartk okay, this is helpful. Since you do know DM locally, he is friends with the same 50yr tech friend [now retired] who was a mentor for me, learned a lot from him about amps, tubes, and more. That was years ago, learning core stuff.

With a nudge from him and a few other friends finally went down the path of quality power conditioning/stabilization to help eliminate any crossover noise with multiple components on the same circuit or junction box. And, another tube amp buddy who convinced [repeatedly] to go with higher quality [extra quiet] external power supplies for my streamer, DAC. He does the same on his CD transports. Things are dead quiet now, dark background, nice subtle details coming through, remaining harshness is gone.  I should have known better, had to experience it 1st hand. We can take this offline and pay a visit with DM locally. I need to call him anyhow fwiw.

@stuartk I remember you mentioned using the same line of cables power cords as ICs in your other thread.
One very easy and free experiment you can conduct put back the stock power cord on the Hegel. Then do the same for the dac. See if and how it changes things. The stock cords normally don’t sound as refined as the upgraded cords do, but they don’t normally introduce harshness. Run the stock cords for a couple of days to let it all settle and sink in. That’s your baseline right there.

@stuartk Forgive me if this 'idea' seems too obvious, but you might try to slightly reposition your speakers, sometimes things can dramatically change within radius of few inches. I would say that I own quite transparent speakers (F.Serblin Accordo) and pretty resolving gear (Burmester 036 amp and Burmester 089 player) with silver cables everywhere, but while in process of finding best position for those speakers in my room, I 'menaged' to make them sound very, very different, all depending on toe in and width between them. That is not my first system and not my first 'rodeo' but differences in sound that went from 'warm and rich' to 'almost clinical' were eye (ear) opening, to say at least. Room acoustics are often taken for granted and speaker positioning is cheapest 'tweak', aldo perhaps the most time consuming. To cut long story short, my point is that if I had no patience to 'play' with positioning I could have swap gear (cables first) in vain. If I were in your shoes, I would mark the current position of speakers and would try to move them in very small steps, half inch 'here' or 'there'. It cant hurt and you may discover that changes might be very impactful. Best of luck

@audphile1 

That's something I never thought of. Will see if I can dig them up. 

@alexatpos 

Thanks. I've experimented with this quite a bit but perhaps not in sufficiently small increments. 

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