PS Audio DirectStream Power Plant 12

[ICUDoc]

I had the same impression of a slight degradation in sound quality when my sub is connected to the Devialet. I got one of these high quality subwoofer isolation transformers, model SUB-2RR from Jensen, and it worked well for me. Works even though my sub is only 2-pin powered (no ground pin). Depends how far you want to go with your tweaks, but something worth exploring IMO.
SUB-2RR | Jensen Transformers (jensen-transformers.com)

Thanks very much, hardcore, I'll have a look at those!