BJTs with higher Hfe should allow to raise R3 By at least 10 times and then a 10uF foil cap could be used at the input. I would then raise R1 to 3,3 Ohm without much penalty.
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I wounder if bootstrapping C3 to the positive supply would be better like in the LM394 circuit.
Look, some years ago :
https://www.diyaudio.com/forums/analogue-source/154210-mpp-1059.html#post4603814
https://www.diyaudio.com/forums/analogue-source/154210-mpp-1059.html#post4603814
This link does not lead to a circuit diagram. Nevertheless the world turns in circles. I know.
The most simple thinks are the most complicated. The last days I have being contemplating how I can improve on the circuit I build. I think I have a version, again with only 3 transistors, that is in some ways an improvement. It should have even lower noise and distortion. Let’s see if I can make it work as intended.
It has been discussed even earlier (post 11508) :
https://www.diyaudio.com/forums/the...owtorch-preamplifier-ii-1151.html#post2508223
https://www.diyaudio.com/forums/the...owtorch-preamplifier-ii-1151.html#post2508223
"Janascard" in Prag used the compound pair as a low noise
amplifier (Fig.1), see also the jfet variation (Fig.4) :
http://www.janascard.cz/PDF/Design of ultra low noise amplifiers.pdf
amplifier (Fig.1), see also the jfet variation (Fig.4) :
http://www.janascard.cz/PDF/Design of ultra low noise amplifiers.pdf
SLNSEPREPRE
This is the circuit I ultimately build. It is not my design. I did only modify it for very low noise and distortion. It is from the Tube Cad Journal. Somewhat obscure but it works beautifully well.
I think I can explain it . I do that later because I am getting a bit busy right now.The calculation of the gain is a bit difficult though.
This is the circuit I ultimately build. It is not my design. I did only modify it for very low noise and distortion. It is from the Tube Cad Journal. Somewhat obscure but it works beautifully well.
I think I can explain it . I do that later because I am getting a bit busy right now.The calculation of the gain is a bit difficult though.
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