agree w/ Aoliviero - Wadia suggests there might be an improvement if the OUTPUTS (not the inputs) are disabled.
(couldnt do it my case as the bottom hex-head screws were jammed over time & broke the tip of my hex-head allen wrench when I exerted pressure)
re. "slighty fuzzy around the edges" - have you played around w/ the diff algorithms? which algo do you have it set on right now?
from my experience w/ the 861, I found that it responds well to several isolation tweaks such as damping the rack as a whole, isolating the 861 from the rack shelf, damping the chassis even more, using after-mkt cones & after-mkt power cord.
Re. the power cord - don't need to spend mega bucks on one. Get one that is correctly made by a manuf who knows what he's doing. Silver Audio, Virtual Dynamics (his down-mkt models) & Signal Cable come to mind.
after you do all this, see if the sound still remains "slighty fuzzy around the edges". The 861 is not plug-and-play. You will not get the best from it using this way.
FWIW. IMHO.