How to proceed?

@stuartk 

Crystal clear. Qobuz stream…but… I can hear the potential for it. It is partially a recording but your components just let it fly. I can 100% guarantee you that if I had those Analysis Plus Silver Apex XLR it would cut thru my eardrums. 

This is something that interconnects like the AZ would most likely tame to a level where it would be listenable. I know exactly what you’re hearing now. This was good!

I’ll add….to further tame this after the interconnects, I would put the AQ Hurricane high power cord on the hegel. Smooth out that bandwidth and add texture and body to the mids.
Don’t sell the DAC it will be a mistake

@stuartk "When I run my Jay’s transport direct into the Hegel’s DAC, fatigue goes away and while there is still some sibilance, it is not nearly so exaggerated."

If this is the case, as you may be wondering, perhaps there is some form of impedance or voltage synergy mismatch going on between your Aqua DAC and the Jays transport that exaggerates the issue somehow [when paired together].

You might be on the right path borrowing/trying different dacs and transport combos paired with your Hegel 390 amp. You already proved the Jays transport does ok with your Hegel amp’s AKM internal dac, directly. A few more steps to narrow it down perhaps.

@stuartk 

perplexing- yet interesting as to why this would suddenly become so apparent to you. I do have a question though. When you set up your new transport did you set it up to run in “over sampling” mode?

@designsfx 

No. The display clearly indicates when oversampling is engaged. Out of curiosity I tried it when I was listening through headphones, tonight. Thin and harsh! Listening through phones with the Hegel dac is much clearer than with Aqua, which sounds very dark by comparison. My headphone setup is very modest- old Grado SR225 through Schiit Jotenheim but the difference is quite apparent