[sdiy] TH XR2206 VCO tune pot

[David G. Dixon]

>  The reference expo current is decided by R43 (bugbrand schematics), isn't
>  it?

Oscar, I haven't looked.  However, which ever resistor determines the
current into the integrator at 0V of CV is the reference-current-determining
resistor.  This is typically hooked up to one of the rails, although it is
often advisable to hook it up to a voltage reference for trackability.