Jam, thanks for your replies.
R10 and R31 will be pots. This is only a prototype design, and rails was chosen because I had that PSU on hand. Resistors from the drains of M1 and M2 is still an option, but with two feedback loops I got better figures of THD in simulations for VAS stage. And I wanted to follow close to JC’s design and his remarks. The same about servo DC. I think, decreasing resistance of R8 and R14 could be require a next stage (e.g. source follower) – the resistance of the VAS output is very high.
Next step would be splitting the rails and lowering rails for the output stage, to run this amp in fully class A.
Regards
R10 and R31 will be pots. This is only a prototype design, and rails was chosen because I had that PSU on hand. Resistors from the drains of M1 and M2 is still an option, but with two feedback loops I got better figures of THD in simulations for VAS stage. And I wanted to follow close to JC’s design and his remarks. The same about servo DC. I think, decreasing resistance of R8 and R14 could be require a next stage (e.g. source follower) – the resistance of the VAS output is very high.
Next step would be splitting the rails and lowering rails for the output stage, to run this amp in fully class A.
Regards
Jarek,
Please keep me informed about your progress and let me know if I can be of any assistance. If it works out, maybe someone could design a pc board for it. I have some ideas about converting it into a balanced bridge design.
Regards,
Jam
Please keep me informed about your progress and let me know if I can be of any assistance. If it works out, maybe someone could design a pc board for it. I have some ideas about converting it into a balanced bridge design.
Regards,
Jam
Re: new wersion
IMO,the VAS stage don't work,the D pin of J3 should connect to the S pin(not D pin)of J1,or to +Vcc,the other rail is same.
jarek said:
IMO,the VAS stage don't work,the D pin of J3 should connect to the S pin(not D pin)of J1,or to +Vcc,the other rail is same.
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