#1
how do active pickups(emg 85 and 81 set) affect the sound on different amps.

a solid state amp (MG100DFX)
and a tube (AVT100X)
#2
Well I wouldn't exactly call the AVT100X tube since it uses 1 preamp tube & a solid-state power section. Honestly I've never really noticed a lot of difference, but I havent used solid state for a while
#3
for a start AVT's are not tube/valve amps. they contain a single preamp valve, where as real marshall tube amps (like the jcm900) contain 4 preamp tubes and 4 power tubes....

so to answer your question on how actives affect the sound...i have no idea