[sdiy] best soundign vco design?

[Mark Romberg]

> One easy place to start is the LM13600 or LM13700 triangle VCO.  Simple
> and single chip core.  The schematic is in the datasheet which can be
> found on the web.  All one needs to add is a proper V-I converter for 
> it
> since the one they show, just a resistor, sucks greatly, even for 
> linear
> applications.  This VCO also provides a square output as well as the
> triangle.

what about the nat semi ICL 3038?  it outputs square, sine and tri 
simultaneously and isnt quite as hard to find as the 13600/13700.  
there's a decent looking schem for a VCO in the application notes that 
you can get from NS.
is there any advantage to one over the other, ie linearity, frequency 
stability, etc?