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From: "Edward Rawde" <invalid@invalid.invalid>
Newsgroups: sci.electronics.design
Subject: Re: Low distortion sinewave oscillator without big capacitor.
Date: Fri, 4 Apr 2025 14:25:29 -0400
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"Bill Sloman" <bill.sloman@ieee.org> wrote in message news:vsnufh$2ou7j$1@dont-email.me...
> On 4/04/2025 11:33 am, JM wrote:
>> On Thu, 3 Apr 2025 19:25:33 -0400, "Edward Rawde"
>> <invalid@invalid.invalid> wrote:
>>
>>> "JM" <sunaecoNoChoppedPork@gmail.com> wrote in message news:qq8tujlpciqc2jrd0ibljmjr9pd37ip6hi@4ax.com...
>>>> On Sun, 30 Mar 2025 14:54:56 -0400, "Edward Rawde"
>>>> <invalid@invalid.invalid> wrote:
>>>>
>>>>> Not long ago JM posted a 1KHz sinewave oscillator with very low distortion.
>>>>> It used a 470uF non polarized capacitor which in practice would probably be made from two 1000uF capacitors.
>>>>> There's nothing wrong with that but I wanted to see whether I could make a working circuit without needing such a large 
>>>>> capacitor.
>
>> You will need to adjust the feedback to suit.  Start with a -5 or -6
>> gain block after the integrator and adjust it's gain until the startup
>> is clean (no saturation).
>
> Here's my version of John May's variation.
>
....

Yes, that works but only 120dB down at 4KHz.
I put the damping resistor back to 47k since I don't care what happens during the first few seonds as long as it happens.
If it's necessary to wait one minute for the purest tone, that's fine with me.

>
> Linewraps are going to be a problem - delete all "\n" from the last few lines

You don't want to remove \n just remove the wraps.

BCM61B does not have two independent transistors.

So you probably want BCM847BS which has two independent matched transistors and a very low price at digikey, so may as well use two 
of them as shown below.

I took the model from
https://github.com/peteut/spice-models/blob/master/nxp/complex_discretes/complex_discretes.txt

It should only be necessary to unwrap the last line of the following.
Don't remove \n just remove the wraps, you may need to use a horizontal scroll bar.

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