Projecting not very difficult amplifier...

[kalach2002]

Seems it`s better-n-easier...

Look:
Decided to use this scheeme solving...
Seems its easier a bit, isn`t it?
**broken link removed**
How to choose last cascade BJTs?

 

[Borber]

new circuit

It's dificult to achieve DC balance in such circuit. What kind of diode VD1 you will use? Output transistors can be 2N3055 and MJE2955 respectively.

 

[kalach2002]

VD1 isn`t a diode its stabilizer (VS), seems it should set DC-mode of VT3, am I wrong?

 

[Borber]

Of cause it's zener diode, but what voltage??? Looks like it is better to use forward biased diode. But amplifier will have poor temperature stability. I wouldn't use such circuit.

 

[kalach2002]

Surely, u`re right...
_______________
Congratulations!!!
Elektroda`s alive!!!

 

[kalach2002]

Tried to find zener diode on 0.6 V, haven`t succeeded, maybe I shoud try to use Ge-transistor instead?

 

[leemarrow]

Hi,
here some good power amplifier with schematic and pcb (pdf format).
http://pssaudio.com/english/1main.htm
can serve for making comparisons

 

[Borber]

Dear kalach,
diode VD1 placed across base and emitter can not be a zener diode. It should be forward biased diode (anode to base and cathode to emitter). Diode current must be set by R8 to achieve DC balance on emitters of VT4, VT5. I must warn you that such a circuit will be very unstable with temperature. You should think about different circuit.

 

[kalach2002]

YOU were Right! In practice, I`ven`t reached any stability of that scheeme,... Errors - best teachers! Choosing another schm...