Single Differential Non-feedback

[lumanauw]

Hi, Lars Clausen,

You are very good with non-feedback power amp design. Just a question. Is it possible to make a non-feedback power amp with just one/single differential? Will it bad in DC offset compared to complementary differential non-feedback power amp?

[Lars Clausen]

lumanauw: Quite impressive website you have :-)

I think you can make the single differential NFB amp, i didn't build it, but something like this should work:

Gain is (R1+R2/330) * (R3+500) / 1000 with shown values approx 120.

[lumanauw]

Hi, Lars,
Thanks. I made it years ago. But it is not for guys like you, since I'm still learning here.
Is there any problem with DC offset stability with single differential non-feedback power amp?

I also a question about other possibility. You like to put big RE (emitor resistor), like in differential to lower local gain. I learned here, that lower local gain can be also made by putting R from collector to base(with base resistor offcourse), to make local feedback. Is this a good option for making non-feedback power amp besides putting big RE?

It is nice that you share an equation of non feedback.

Gain is (R1+R2/330) * (R3+500) / 1000 with shown values approx 120.

R1+R2 (not R1//R2, right?)/330 I understand. The 500 comes from 1k DC pot/2, right?. But where the 1000 comes from?

[lumanauw]

Hi, Lars Clausen,
What do you think of Error Correction (EC) like Hawksford?