[sdiy] CV mixer trouble

[David G Dixon]

> > So, now, the question is, how do you get a 5V reference 
> from the -15V rail?
> 
> Well, if you're going to use the -15V rail as a reference 
> (dumb idea but lets follow it) then you just need a single resistor.

Yes, of course.  Duh!  A resistor 3 times larger than the CV input resistor.
What WAS I thinking?

Of course, if one has a pile of equal-sized precision resistors in one
value, then using three is a good option.

In my own builds, I take CV references from the rail in non-critical
applications such as VCFs, and take them from temperature-stable voltage
references (such as REF02) in critical applications such as VCOs.  In those
cases, I buffer the reference output to alleviate the current restriction,
and then send this buffered output all over the board.