[sdiy] Interesting article on top octave generators.

[Roman Sowa]

The thresholds in 40106, which define oscillator stability, are not even 
specified with regards to temperature or long term drift or any other 
drift. They may differ a lot from part to part, and nobody cares, 
because it's not the intention  of 40106 to be a timing device. Its 
operation relies on Vgs voltages and who knows what else, and that 
voltage greatly depends on temperature.

Sure it's nice simple oscillator, like many others, but not all of them 
would be my first choice for tuning source. But for a drone, why not. 
Last year I've made a board which contains 24 such oscillators, voltage 
controlled, for a drone. And it's less than 1 inch squared.

Roman


W dniu 2024-12-30 o 19:49, David G Dixon pisze:
> A CD40106 oscillator is just a schmitt trigger, a cap, and a resistor.  
> Presuming the supplied voltages are well regulated and the caps are of 
> decent quality, then why should one expect anything other than perfect 
> stability?  If I were looking for fixed-frequency square-wave 
> oscillators, that would also be my first choice, cuz it's so simple, and 
> one can fit all 12 oscillators onto a board that's about 4 inches 
> squared, even with through-hole components.
> 
> ------------------------------------------------------------------------
> *From:* Synth-diy [mailto:synth-diy-bounces at synth-diy.org] *On Behalf Of 
> *Roman via Synth-diy
> *Sent:* Monday, December 30, 2024 12:01 AM
> *Cc:* synth-diy at synth-diy org
> *Subject:* Re: [sdiy] Interesting article on top octave generators.
> 
> Not only from the 70's. There's this one guy who makes combo organ 
> eurorack module the hard way, with TOG, dividers and discrete circuitry 
> all the way down from there. He uses 12 tunable oscillators. And what is 
> most surprising, he uses 2 hex Schmit hex inverter chips for that 
> without any problems of stability.
> 
> 
> Roman
>