ok, i've seen many people talk about putting the obp3 into their thumb bass. what i don't get, is that the obp3 requires 5 knobs (2 of which are stacked) bass, mid, treble, blend, vol. the thumbs has 4 knobs. what do you do? drill another hole? leave one off? also, are the stock pots in the thumb correct for this preamp? I asked aguilar all these questions & they said that they didn't know my bass (idiotic, who else would know the answers to these questions? am i just supposed to buy it & figure it out myself & if not be stuck with a $179 preamp that i can't use? jeez)... anyways sory for the rant, it's just terrible customer service. if they sell a replacement part, they should know how it gets installed. any hints on how to do this?