[sdiy] VCO tuning philosophy re-visited

[lanterma at ece.gatech.edu]

On Feb 7, 2011, at 2:04 AM, Ian Fritz wrote:

> Right. The DD uses an LM331 V-F converter in its core. This works on the charge balance principle, which does indeed involve a charge injector.  This chip has phenomenal 0.01% tracking, which is a consequence of the integrating current flowing over the whole period of a cycle (no error due to discharge time).

Hi Ian,

Would you recommend the LM331 for use in regular audio VCOs too (i.e., non-ultrasonic ones)?

Any thoughts on whether it's better or worse than the XR4151 used in the Chroma?

- Aaron