[sdiy] Clock noise problem

[David G Dixon]

> > Is it possible the clock noise is coupling onto the audio outputs 
> > purely due to the proximity of the circuits?
> 
> Yes it is possible.  Even more so if you're analogue circuit 
> is high-impedance.

Oh yeah.  I have a CV circuit for a matrix keyboard which is clocked by a
CD40106 schmitt trigger.  I naively ran the clock trace parallel to a
high-impedance trace from the R2R ladder to the output buffer for a couple
of inches, and the interaction was fairly severe.  I fixed it by putting
small resistors and filtering caps on the output, but ideally those traces
wouldn't be anywhere near each other.  Lesson learned.