LM13700 - Anyone familiar with prototyping VCOs using this chip please?

[Paul Perry (Frostwave)]

Modular synth circuits may appear over engineered - but there is often a reason: they aren't designed for rock & roll.
In the case of a voltage controlled oscillator, you need precision of better than a few hundred parts per million, if you want to stay in tune.

And if you are doing minimalist ambient stuff, the noise level has to be REALLY low.
For example, to be usable in an electromusic studio, ring modulator bleedthrough should be 60dB down or better (thats one part per million!).