So I'm trying to figure out the best way to run this setup as I just found out we won't be using our own mixer for a bigger show we have next Sunday. I only need to be able to hear myself and the click track. I've got a Behringer Powerplay Pro-XL HA4700 (4 channel headphone amp) I just ordered a Hughes & Kettner red box 5 And I use an ENGL Invader 100 I'm being told I need to get a DBX GoRack, but I'm trying to determine whether or not that is necessary. Will I be able to do (hear) what I need to with just the headphone amp and DI box? And how should I have that set up exactly?