Bongo is absolutely right - so is everyone else here.
EQ's are for (and elaborate EQ's are even greater for) adjusting for room acoustics. Every time you use your EQ to shape your sound, you change what it's going to do in the room you're playing in. Therefore, you can dial in a great EQ to get your bass to sound just the way you want it at home, then take the same settings to your next gig and it sounds like crap.
The bass enters into it when you realize that different woods enhance different tonal ranges - harder woods give more high presence and softer woods bring out the midrange more.
Leave the EQ flat on your amp head, and just use some of the boost on your bass' EQ. If you've got two pickups on it, you should get enough variance to suit your playing situations, or it's time for a modification. I stuck a Bartolini 3 band pre-amp in both of my inexpensive Brices and the control difference is incredible. The only thing I touch on my Behringer head is the "shape" control for different music "styles" (besides, all the treble control does is increase hiss). Or the "bright" or "deep" buttons for a little boost in either direction. The "shape" lets you control your mids.
The best sound I've ever got from either of them is going into my computer through a Mackie mixer, with just a little bass boost from the mixer eq. Any amp/amp head I've played them through (GK, Carvin, Behringer, MarkBass, Crate, etc.) makes them sound like garbage. Best sound ever - a 30 year old Polytone - NOTHING like it out there today.
When you upgrade, though, I'd be interested in securing your 2-10 and 1-15....
