[sdiy] NPN pair VCF?

[David G. Dixon]

> The Pin 2(7)of CA3280 may also be used for source current when when pin
> 1,(8) not used.

I must confess I haven't explored the CA3280 yet.  I'm still having way too
much fun with the LM13700.

I see that pin 2(7) connects to the emitters of the diff amp trannies.  Are
you suggesting that this could be rigged up to an external "do-it-yourself"
current sink in such a way as to provide current-sinking gain control?  Or
are there some other clever uses for these pins?