Hello and thank you very much again for all the kind and valuable help.
I have come to the conclusion that all the projects you mention when correctly implemented would sound very very good.
If any difference there could be maybe only an instruments could show them.
It is time to start for me to do something ... i have more info than i need.
Sorry, what thread are you referring at ? 😀
Seriously i would love to have the opportunity one day to listen to such famous preamp.
It must be really something special.
Thanks again and kind regards, gino
How could you not 😉
This should keep you busy for a few years 😀
Part 1,
http://www.diyaudio.com/forums/solid-state/71189-john-curls-blowtorch-preamplifier.html
Part 2,
http://www.diyaudio.com/forums/lounge/146693-john-curls-blowtorch-preamplifier-part-ii.html
Hello ! it was a joke ... of course i am well aware of the mighty 3D 😱
My point is that being a line stage this lengthy and challenging discussion shows how much interest line stages provoke
And i have a soft spot for line stages in particular ... so i share the very same interest.
I am reading it hoping to understand some bits.
Thanks again and kind regards, gino
My point is that being a line stage this lengthy and challenging discussion shows how much interest line stages provoke
And i have a soft spot for line stages in particular ... so i share the very same interest.
I am reading it hoping to understand some bits.
Thanks again and kind regards, gino
Hi and i promise ... the last weird question.
In the waiting to get one of this simulation SWs (i am a little scared now because someone told me that they are everything but user friendly 🙁) i have a weird but short question.
Hopefully it will lead to a short answer 😱
Taken this very basic circuit ... (please do not consider C2)
just to understand ... every other things equal, which of this two conditions will lead to less distortion ?
Case 1) Vce = 40V ; Ibias = 10 mA
Case 2) Vce = 20V ; Ibias = 20mA
I mean, to get lower distortion it would be better to go with an increase of Vce or of Ibias ?
Because i have something in mind of very very wicked ... 😱 😉
Sorry for the very basic maybe trivial question, but i am at bottom level in knowledge and i can tell you it is not easy to find a paper/book describing clearly and easily the basic concepts.
I would jump on it immediately
Thanks a lot again to all for the kind and valuable support
Kindest regards, gino
In the waiting to get one of this simulation SWs (i am a little scared now because someone told me that they are everything but user friendly 🙁) i have a weird but short question.
Hopefully it will lead to a short answer 😱
Taken this very basic circuit ... (please do not consider C2)
just to understand ... every other things equal, which of this two conditions will lead to less distortion ?
Case 1) Vce = 40V ; Ibias = 10 mA
Case 2) Vce = 20V ; Ibias = 20mA
I mean, to get lower distortion it would be better to go with an increase of Vce or of Ibias ?
Because i have something in mind of very very wicked ... 😱 😉
Sorry for the very basic maybe trivial question, but i am at bottom level in knowledge and i can tell you it is not easy to find a paper/book describing clearly and easily the basic concepts.
I would jump on it immediately
Thanks a lot again to all for the kind and valuable support
Kindest regards, gino
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I'm not an AC man, but I'd suggest that the ratio of Voutput:Vce controls distortion.
If Vout/Vce is near 1 then distortion is high.
If Vout/Vce is <<1 then distortion is lower.
You don't say what your Vout is, but for a set Vout I think that high Vce is lower distortion.
If I'm wrong please tell us.
If Vout/Vce is near 1 then distortion is high.
If Vout/Vce is <<1 then distortion is lower.
You don't say what your Vout is, but for a set Vout I think that high Vce is lower distortion.
If I'm wrong please tell us.
Distortion in the textbook BJT grounded emitter circuit comes mainly from the exponential Vbe characteristic. If the emitter is bypassed then the only way to reduce distortion is to reduce the input voltage. A bit of maths based on the Ebers-Moll BJT model shows that the percentage second-harmonic distortion in the output is equal to the peak input voltage in mV (i.e. 1.4 times the RMS input voltage).
If the emitter is unbypassed then the distortion depends on the ratio of Re to the intrinsic non-linear emitter resistance (which depends on current). Basically, to get lower distortion you need more current or a bigger emitter resistor so you need to maximise the voltage drop across Re. This will, of course, minimise the allowable output voltage swing so a compromise is necessary.
This is why the classic textbook circuit is rarely used in audio, and why most SS circuits use lots of feedback.
If the emitter is unbypassed then the distortion depends on the ratio of Re to the intrinsic non-linear emitter resistance (which depends on current). Basically, to get lower distortion you need more current or a bigger emitter resistor so you need to maximise the voltage drop across Re. This will, of course, minimise the allowable output voltage swing so a compromise is necessary.
This is why the classic textbook circuit is rarely used in audio, and why most SS circuits use lots of feedback.
Hi and thanks alot indeed
This is exactly what i wanted to know.
Vout will be at maximum 2V ... but you have perfectly solved my doubt.
Then i wonder which effect can have a Ibias increase 😕
But i am mostly interested in distortion of course.
Thanks again and kind regards, gino
Hi thanks and sorry ... i put a bad picture, cancel the bypass C2
What i wanted to know is that an increase in Vce acts reducing distortion
I am done with this.
If i understand well there is not possible that this circuit could be used alone for audio purpose ...
I was very curious ... now i know better. I need to try these sim SWs
They should be very useful to solve these basic issues i guess.
Thanks a lot indeed.
Kindest regards, gino
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