i still poorly understand how to frequency tune this thing . . . but the main concept has been achieved -- a pure undistorted sine wave form for crystal . . .
. . . i find it curious that the appropriate web search can't find any analog circuits for such . . . . . . . . . even more curious is the fact that most micro controllers use digital/discreet stages based quartz drivers that for lower frequency X-tal-s as far as i get attempt to over stress the device and eventually ruin or kill it ???
(8 billion people with no brain on this planet ... statistically impossible but is what the prolonged web search stat.-s retrieves - i roger it but i can't get it - it's insane)
update 2017.04.10 21:41 UTC+3h : revised an old design -- not as good as previous but seemingly near the sine -- also uses a lot of less power -- it likely would work and with even less power but assumingly with longer startup time