From past experience, I recommend one of these two options...
Sadowsky Outboard Preamp (gives you at least bass/treble boost options)
or
the very cheap option... ART Tube MP Studio mic preamp.
The ART has NO EQ functions at all, but it offers a ton of clean gain, tube warmth, and is CHEAP. $29 at Musician's Friend right now. All of my basses are active, but I still use this in front of my solid state heads to warm them up, and I also use it as a main preamp for my double bass (w/Realist pickup). If you want 3-band EQ control, the Aguilar seems logical, but you can always control EQ at the amp, which I'm guessing you already do since it's a passive bass.
I owned one of those Corvette Standards once.... a passive fretless model. Sounded great and was beautiful & built like a tank, but weighed a ton and never fit my body comfortably. The tone was wonderful though!