Bipolar OP Stage Error Correction

[clem_o]

Originally posted by AndrewT
and the other half can't open it.

Thanks for putting up the pic, powerbecker...

Hi Andrew,

What seems to be the problem? I''ve managed to open the file as well, though haven't had the time to play with it...

Cheers!

[Bonsai]

my error - they should both be set to very low values or removed - I was playing around with the values before I posted. Note I did my sims with R1 and R2 = 10 Ohms.

[Bonsai]

Some minor corrections and I've used more conventional resistor values. Distortion now down to 0.02 at 20KHz into 8 Ohms and 0.1 into 2 Ohms.

This is quite a good result and I'd expect after placing 20-30dB global feedback around this stage (i.e. as in a complete amplifier system), distortion would be very low.

[lineup]

Originally posted by Bonsai
Some minor corrections and I've used more conventional resistor values. Distortion now down to 0.02 at 20KHz into 8 Ohms and 0.1 into 2 Ohms.

This is quite a good result and I'd expect after placing 20-30dB global feedback around this stage (i.e. as in a complete amplifier system), distortion would be very low.

this will be very interesting, to see your results

good linearity in each stage, also in the output stage
via local resistor degeneration feedbacks
or using other local feedback techniques

this is the way to good linearity and low overall power amplifier distortion
- and possibly fast amplifiers keeping linearity

-----------------------------------------------


we have read many times in forum:
global feedback is good .... used in the right way
but not when used as a substitute for bad design and great in-linearity in the local stages

good properly designed local stages
reduces the call for high amounts of global feedback
= high closed loop feedback factor
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This has been expressed, one way or another,
by just about any good knowledge amplifier person
in this forum
Including the Very Master of practical use of This design method: NELSON PASS
and another sensible clever OldTimer: HUGH 'AKSA' DEAN


good luck boys!
you are on the very right track here
and in very very good company


Regards
lineup
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