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power amp circuit

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Zero999:

--- Quote from: NASK on July 31, 2018, 09:16:47 am ---Now it is working with symmetrical!

--- End quote ---
That looks pretty badly distorted, better than before, but still not good and the waveform is far from symmetrical.

EDIT:
It's more obvious it isn't symmetrical, after the bottom half of the signal is flipped over, i.e. fullwave rectification. Look the amplitude of the negative half, doesn't even match the positive and it's skewed horribly.

JS:
You could use an opamp inside the loop to increase the open loop gain, getting more feedback to correct the distortion, here is a simple circuit that works nice, as you see it allows you to add a DC servo to eliminate DC and not needing an external cap if running from dual rails. You could use it or ignore it and use the thing like an opamp.

http://www.jlmaudio.com/JLM%20Hybrid%20Opamp%20circuit.pdf

JS

Zero999:

--- Quote from: JS on July 31, 2018, 03:34:21 pm ---You could use an opamp inside the loop to increase the open loop gain, getting more feedback to correct the distortion, here is a simple circuit that works nice, as you see it allows you to add a DC servo to eliminate DC and not needing an external cap if running from dual rails. You could use it or ignore it and use the thing like an opamp.

http://www.jlmaudio.com/JLM%20Hybrid%20Opamp%20circuit.pdf

JS

--- End quote ---
I already suggested a similar thing a few posts ago, but the original poster wants a discrete design. I'd suggest a discrete op-amp, but it might be too complicated.

JS:

--- Quote from: Hero999 on July 31, 2018, 03:43:51 pm ---
--- Quote from: JS on July 31, 2018, 03:34:21 pm ---You could use an opamp inside the loop to increase the open loop gain, getting more feedback to correct the distortion, here is a simple circuit that works nice, as you see it allows you to add a DC servo to eliminate DC and not needing an external cap if running from dual rails. You could use it or ignore it and use the thing like an opamp.

http://www.jlmaudio.com/JLM%20Hybrid%20Opamp%20circuit.pdf

JS

--- End quote ---
I already suggested a similar thing a few posts ago, but the original poster wants a discrete design. I'd suggest a discrete op-amp, but it might be too complicated.

--- End quote ---
A discrete opamp might not be too complicated, 5 transistors could do. Here ia a design I've used in the past, for low bandwidth should be good enough, like audio band, something like 40dB of open loop but it can reduce crossover distortion quite a bit.

JS

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