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From: Bill Sloman <bill.sloman@ieee.org>
Newsgroups: sci.electronics.design
Subject: Re: A variation on my current mirror low distortion sine wave
 oscillator - 10dB less distortion and much the same number of components
Date: Sun, 16 Feb 2025 16:19:04 +1100
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On 16/02/2025 2:18 pm, Edward Rawde wrote:
> "JM" <sunaecoNoChoppedPork@gmail.com> wrote in message news:gp6vqjl5oma32tga136kspreh7a8182ofg@4ax.com...
>> On Mon, 10 Feb 2025 17:18:01 +1100, Bill Sloman <bill.sloman@ieee.org>
>> wrote:
>>
>>> Basically same idea, but two separate controllable asymmetric current
>>> mirrors, rather than one, and no current steering. The half-wave
>>> rectifier still seems to be the source of the distortion in the
>>> stabilised output.
>>>
>>> C25 and C26 take out as much of it as I can. Increasing them - from 15nF
>>> to 33nF makes the distortion worse. Splitting the resistors into three
>>> rather than two and adding two more capacitors might help, but what this
>>> circuit needs is more insight, rather than more components.
>>
>> What is the point of a push-pull current mirror?  You don't need
>> response at dc.  A "class A" (for want of a better term) mirror with
>> minimal current deviation will have distortion levels orders of
>> magnitude less than the circuit you propose.
>>
> 
> Is there any specific reason for the npn Q5?
> Replacing it and R25 with a single 100k resistor from U2 to Q1 base seems to work just as well.
> 2kHz is 141dB down measured with cursors on a zoomed in FFT in LTSPice 24.1.2

Complementary pairs often work better than simple emitter followers. 
John May probably has a good reason for the choice. I've used them from 
time to time.

https://en.wikipedia.org/wiki/Sziklai_pair

-- 
Bill Sloman, Sydney