VTL, preamps are not a good match with SS amps,
will sound dull and very dry, lacking detail and punch,
if you are matching VTL 5.5, with solid state amps, dont'waist your time trying to make it sound good,
I whent through the same ordeal, and after spending a small fortune on NOS tubes without any success, replaced my Belles amp for Quick silver V4 amps, and I,m in heaven;
How does your system sounds with that match up?