i've palyed the ampeg and am quite fond of it. i can get one new old stock for $350. how does it compare to the sansamp rbi rackmount? how flexible is the rbi? i would use the ampeg as my main preamp and just use my hartke 7000 as a power amp. the rbi would most likely go in the effects loop, but still i'm not sure... any one use the rbi as a main pre amp? thanks for all replies and info in advance!