Has the next logical upgrade to the 802 D2 not occurred to you ?
I own that speaker, bypassed the 803. I can’t comment on the Gryphon.
One problem that remains with the 802 is in my space throughout my system
changes it seems to perform best at a somewhat limited volume range of almost
loud to loud. It’s possible that many speakers perform best at a particular setting.
Could also be my room.
But my big issue was high frequency harshness which I solved when I moved from
a solid state preamp, Boulder 810 to BAT Rex the sound stage just opened up so
nicely with lots more subtle air banishing any vestige of harshness I was induring
with the Boulder. But that’s not your problem.
I was able to keep the Boulder mono block 850s in, 200 watts apiece. Later I
upgraded to the Innuos Statement server and Rossini Dac and that just continued
the improvements. I think the Rex rolls of the very highest frequencies but I could
still hear many of the new digital refinements and added soundstage dimensions.
Those things seemed very complimentary.
Never owned Gryphon but have heard them with Rockports, probably with the
Diablo. That system didn’t suffer from the high frequency strain I had on my
Boulder pre but it was nowhere near as open and engaging as my system with the
Rex pre. That system seemed constrained but then that room seemed over large.
You might try putting in a very nice tube preamp, if the Diablo has amp inputs and
see what that does for you. I think there is a synergy between tubes and the
diamond tweeters. In general my experience with the 802s is that I can make a lot
of other improvements that are all very much revealed. But if I were contemplating
my next speaker upgrade I would be looking for a larger leap. Perhaps checking
out a Vinberg or Tidal.
I find advice is often wanted but difficult to digest.