[sdiy] current mirror for NPN expo?

[David G Dixon]

> can anyone point me towards info on how to use ONE NPN EXPO 
> to drive two vcos?

Can't you just mirror the current-sourcing one?  I.e., tie its emitter to
the other two, and connect its base to the other current-sourcing one?  You
should be able to replicate the current as many times as you want this way.
I did it with five transistors in a four-pole filter once; it worked a
treat.