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From: "Edward Rawde" <invalid@invalid.invalid>
Newsgroups: sci.electronics.design
Subject: Re: Random thoughts on sinewave oscillators
Date: Fri, 18 Oct 2024 13:47:02 -0400
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"Cursitor Doom" <cd999666@notformail.com> wrote in message news:veu45s$3cmo3$5@dont-email.me...
> On Fri, 18 Oct 2024 11:25:19 -0400, Edward Rawde wrote:
>
>> "piglet" <erichpwagner@hotmail.com> wrote in message
>> news:vetde5$38sbk$1@dont-email.me...
>>> Edward Rawde <invalid@invalid.invalid> wrote:
>>>>
>>>> The circuit below produces a reasonable looking sinewave but the rise
>>>> time still seems to be slower than the fall time. It may be that the
>>>> amplifier in use is not ideal for this.
>>>>
>>>>
>>> Could that just be second harmonic distortion? You could test the
>>> amplifier by uncoupling the Wien network and injecting test inputs.
>>>
>>> Elsewhere I think your amplitude control problems could be simply due
>>> to too much gain.
>>
>> Perhaps, but I've not so far been able to get the circuit I posted in
>> response to Bill to produce a sine wave no matter what I do with the
>> control loop gain.
>> It either grows to clipping or dies.
>
> That's the main purpose behind having a thermistor or filament bulb in the
> f/b path.

Sure, but why use thermistors or filaments if you don't have to?
Filaments don't last forever, particularly not if you drop your equipment, and filaments make me think of something like a 5U4.
I forget when I last saw a filament. House lamps don't even have them now.

I'm trying to make a low cost oscillator which produces the cleanest 1K Hz sinewave I can get, using only resistors, capacitors and 
semiconductors.

There are plenty of examples online, but some of them don't seem to simulate.
Whether that's because they do work in reality but not in simulation is hard to say.