rob67 OP
I now have a Gryphon Antileon Signature amp.
In comparison find the set-up a little dark or rolled off in the highs.
I tried a PASS X2.5 in place of the Ref5se and the top end opened up.
My friend has this Gryphon Antilleon Evo Signature with Wilson Alexia MkII and with my passive pre feeding it, it is pure magic with all the highs and lows and dynamic slam you could wish for.
My opinion is your tube pre or phono stage is rolling off the highs.
Cheers George