I've used both Rane and DBX graphic equalizers for my old rigs and they are equally great eq's. The DBX 2031 is newer than the Rane GE30. The 2031 also has a:
" a. noise reduction circuit which increases S/N ratio by up to 20dB
b. peak limiter that allows you to tame the wildest hits or the subtlest nuances of any signal"
Some folks prefer recognizable name brands that have proven performance, and so so may opt for the Rane. But for me, the DBX is the shizzle.
Besides, it already comes with a power supply adapter. Good luck.