I have a Zenith Mk.3, the sound is stunning and represents a very noticeable upgrade over the solution it replaced (SGC i5 + LPS for Roon Core, Synology NAS, opticalRendu + LPS).
I am running Roon Core and Roon player from the Zenith. I’m also using a Stealth T-Select USB cable as my primary interface to my Lampizator DAC. After reading your post, I tired my printer cable in place of the Stealth and the sound definitely took a hit. So your USB cable could be a limiting factor.
I don’t know much about the Accuphase DAC.
I am running Roon Core and Roon player from the Zenith. I’m also using a Stealth T-Select USB cable as my primary interface to my Lampizator DAC. After reading your post, I tired my printer cable in place of the Stealth and the sound definitely took a hit. So your USB cable could be a limiting factor.
I don’t know much about the Accuphase DAC.