Now that is interesting! Well, it is if by "active" you mean feedback "Baxendall" types? These are strictly verboten in guitar amps! I don't know of even one design that uses them, all subscribe to the passive "tonestack" or totem pole design.
The big advantage of feedback tone controls is of course virtually no interaction between bass, mid and treble where as passive stacks are horribly (or nicely! Yer pays yer money!) interactive and gitist (say they!) LOVE that!
Must look for some active bass and 6'er shcemos..
Dave.