If all of your components and cables were chosen for their reputation of being highly detailed the presentation can lean too far in that direction. The leading edges of instruments and vocals are a little over emphasized and sibilance happens. A warmer cable in the mix might eliminate that and restore the balance. WireWorld and Cardas come to mind if you decide to try.The silver coated cable you're using might too much used throughout.
How to proceed?
Removing my Aqua La Voce dac from my system has eliminated fatigue and reduced but not fully eliminated sibilance. Running my Jay’s CDT2MKIII into my Hegel H390’s onboard dac is definitely a more relaxed presentation but tonally leaner than I prefer. Some have suggested I swap out the Hegel, but first I’d like to try another dac.
What I’m unclear about is how to go about choosing another dac that will not duplicate the same drawbacks I’ve experienced with the Aqua. Are there details in the design or specs that can guide me in this regard? I'm unsure how to proceed.