I found the schematic for the MB500 Fusion head, which uses a 500k linear taper pot.  I'll give it a shot, but does anyone have any experience with the GK-style contour/"voicing filters" that are used on a lot of bass amps?  Any suggestions?

I actually bought the MB110 while searching for a better quality/higher wattage amp similar to the Crate BX25 combo, which I've had around for years and years but only recently tried reamping guitar through and was blown away.  The Crate has a "Shape" knob and an on/off switch for the Contour, and 100% sounds very similar to the GK, but I keep it at 50% and it sounds great. 

My mistake - I was thinking of the MB500 and larger models that have the Contour knob.

Would you happen to know the value and taper of the pot used in those model?

Thanks for the quick and thorough reply!

I have a Gallien-Krueger MB110 that I really like, but I wish that it had the adjustable Contour knob of the MB200 head instead of the on/off Contour switch.  Are the circuit boards similar enough that it could be modded?