[sdiy] AN299 VCO (was: SDIY list troubles)

[Samppa Tolvanen]

On 4/29/08, flight <flightofharmony at comcast.net> wrote:
> Last year I spent a few weeks playing around with this circuit. I used a
>  TL074, which worked fine. The VCO works nice except for its horrible drift -
>  I probably should have insulated the CA3046 from stray air currents. I
>  abandoned the project finally, as I just couldn't get it to stabilize. I ran
>  it for up to 5 hours and it just wouldn't sit still! It also has a lengthy
>  warm-up period while the array heats up (5+ mins). Here's the schematic I
>  drew from the App Note: http://www.flightofharmony.com/stash/AN299 VCO.pdf .
>

Ahha.

Are we back to Ian Fritz Electronotes clone (?) circuit
(http://home.comcast.net/~ijfritz/sy_cir2.htm with some mods) for some
stability in expo/tempco driven sawtooth cores? You don't specify any
figures for the drift.

Samppa