I ran the D800 at rehearsal tonight. The cab at the jam space is an Epifani T-212 with a blown tweeter so it's usually pretty thuddy and indistinct. I did happen to have newish GHS balanced nickels which have more top end than my usual broken-in sunbeams... it did seem more articulate and intelligible but there are a lot of factors in play there... It was weird bringing the master volume to 11:30 for a rehearsal, but I know the knobs are designed to be effective through 100% of their range unlike most amps, so I wasn't worried that it was out of juice.
I do wish the high mids were voiced at least 2x as high. But I have an 800hz knob on one bass and 1k on the other, so I can use the on -board pre for a mid bump when I need it.
I'm really looking forward to next Friday when I take the whole rig including fEARful 12/6s out for a gig where I'm providing backline... always love getting to hear my gear from in front of the stage!
Absolutely love my D800 through every Greenboy I've owned.. presently an F112..