Scott Bernardi lockbox lin/exp VCA

[gdavis]

Does anybody here have any experience with the linear/exponential VCA by Scott Bernardi?

http://www.bernacomp.com/elec/lockbox/lockbox_vca_oper.html

I'd like to use it in my synth design but I've put it into spice and it's not behaving as I expected.

The linear CV input seems to be OK (0V = off, 10V = full on) but the exponential CV input seems off. He has trimmer RV10 between GND and V+, but this makes the CV input so that 0 is full on and negative values attenuate. Is this correct? I thought it should take CV inputs of 0V (off) to +10V (full on) but in order to get this I have to connect the trimmer to V- instead of V+ and trim it to nearly -15V.

So while I can make it work the way I expected, I was wondering if anyone had any insight as to how it's intended to work in case I'm missing something.