Distortion in darlington amplifier

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Stan2020 said:
I am planning to make was proven to be functional, reproduced in thousands in1960th...although even today there are hot arguments on how and why actually it works
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Nothing magic or even arguable about that; it's a basic super regenerative circuit, probably a squegging / quenching type with the diode and cap in the bias circuit of the second transistor acting as the quench system.

Regenerative circuit - Wikipedia

en.wikipedia.org

Super Regenerative Receiver: Super-Regen Radio » Electronics Notes

Discover what a super regenerative radio, super regen is, how it works, its uses, and much more . . .
www.electronics-notes.com

ps. note that "Radio amateur" has a specific legal meaning in many countries; it's someone who holds an Amateur Radio (aka Ham) licence qualification.
Many people on here are radio amateurs, as well as professional electronics engineers.
 
rjenkinsgb said:
Nothing magic or even arguable about that; it's a basic super regenerative circuit, probably a squegging / quenching type with the diode and cap in the bias circuit of the second transistor acting as the quench system.
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And basically came from the even older valve designs, there's not really been that much 'new' in radio, for a very, very long time.

As I recall super-regens are frowned upon these days (decades) as they transmit large quantities if interference, so 'modern' ones tended to have a an RF stage before them, to reduce the interference reaching the aerial.
 
rjenkinsgb said:
Nothing magic or even arguable about that; it's a basic super regenerative circuit, probably a squegging / quenching type with the diode and cap in the bias circuit of the second transistor acting as the quench system.
Click to expand...
I don't think this is super-regen.
Where do you see a positive feedback and oscillator here?
It is a basic reflex circuit, with unusual detector (diode in series with capacitor). Here is the complete diagram:


rjenkinsgb said:
ps. note that "Radio amateur" has a specific legal meaning in many countries; it's someone who holds an Amateur Radio (aka Ham) licence qualification.
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I am aware. This is my second language. So what would be the appropriate word for those who just have electronics as a hobby?
 
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Stan2020 said:
It is a basic reflex circuit, with unusual detector (diode in series with capacitor). Here is the complete diagram:
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No.
A "Reflex" circuit loops the detected audio back and uses some of the RF stages to amplify that, then separates the two again.

The regenerative feedback in that circuit would be loose coupling from L6 to L5.
 
rjenkinsgb said:
No.
A "Reflex" circuit loops the detected audio back and uses some of the RF stages to amplify that, then separates the two again.

The regenerative feedback in that circuit would be loose coupling from L6 to L5.
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There's so much wrong with that 'circuit' it's hard to know what it's supposed to be doing

However, as I see it, L6 is probably an RF choke, and it's 'supposed' to be a reflex circuit, feeding the audio back via VD1.

But presumably it's yet another non-working circuit he's found on some young kids webpage?.

Must say though I'm quite bemused by the tuning switching, switching two coils in series or parallel - I've no idea how well that would or wouldn't work, as it's not something I've ever seen done?.
 
rjenkinsgb said:
No.
A "Reflex" circuit loops the detected audio back and uses some of the RF stages to amplify that, then separates the two again.
The regenerative feedback in that circuit would be loose coupling from L6 to L5.
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Yes.
It IS a reflex receiver. L6 is not related to L5. L5/L4 is an RF transformer, L6 an inductance load of final stage of RF/first stage of audio amp.
 
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You have to learn a lot, Nigel (well, at least you did not see a super-regen here! ). This is a famous (or infamous) circuit published in 1958 and it won a first prize on country-wide exhibition. Was reproduced by thousands of radio-amateurs (radio-hobbyists?). Kind of a legend. Strange implementation of detector and technically should not work. But it does. At least it did, and this is probably the most interesting thing. Current explanation (one of) is that this construction was adjusted for low quality components available in 1950th, with reverse current of up to 0.1mA. Modern diodes are way better and THAT might make it hard to reproduce today.
BTW, switching MW/LW also worked without any issues; I am not going to implement that, there is no LW broadcasting in my area.
 
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I'm slowly coming to the conclusion that the OP is just a troll, he seems to be deliberately posting the most stupid and useless circuits he can find, and then ignoring any sensible advice about them - I fear his continuance here may be short lived?. I think we've already wasted far too much time on him?.
 
It has become a BS thread with no effort on his side to resolve his own question.
 
Nigel Goodwin said:
I'm slowly coming to the conclusion that the OP is just a troll, he seems to be deliberately posting the most stupid and useless circuits he can find, and then ignoring any sensible advice about them
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Is this so?
I just posted a schematics of reflex receiver very popular in 1960th; this device took a prize and diploma at state-wide exhibition in 1959. I am going to assemble it. You claimed this circuit is " found on some young kids webpage". If this is not arrogance then what is?
What actually stopped you from asking something like 'where from did you get this schematics and are you sure it is functional?'
This is how polite and educated people should behave. Instead you are accusing me of ' deliberately posting the most stupid and useless circuits '.

Sapienty sat.
 
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And maybe the op should of posted the whole thing


As you can see there was a change to VT4
 
rjenkinsgb said:
Your very first post:


Then you argue just about everything said by a number of professional electronics engineers and designers.

How do you expect people to react to that???
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Please forgive me for writing 'I am not good at electronics'. Looks like I should have entered as others self-proclaimed "professional electronics engineers and designers" here and then you wouldn't feel so disappointed.
Regarding your second question:
from professionals I'd expect them listen to the arguments regardless of how I introduced myself. For professionals the subject means way more then personal ambitions. For professionals, when someone disagree with them, they listen and try to understand first. They don't throw arrogant claims ' stupid and useless', ' found on some young kids webpage' etc. But this is for professionals. Enjoy your self-importance.
 
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be80be said:
And maybe the op should of posted the whole thing
As you can see there was a change to VT4
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What change are you talking about? Small fragment on right? This is an optional recent modification for volume control. Original schematics does not have it.
 
be80be said:
Maybe it be nice to post the whole story
V. Plotnikov, published in the journal "Radio" No. 11 - 1959.
For those radio amateurs who want to read the original full author's description of the article by V. Plotnikov - the link is posted here.
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Speaking of whole story you are wrong again. Original schematics was published by him in 1958, later on he added some improvements (and, supposedly, a mistake with detector).
 
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